Savory Tennessee Onions Bake Recipe – Easy Cheesy Casserole Dinner

Name: Savory Tennessee Onions Bake
Prep time: 15 min
Cook time: 40 min
Total time: 55 min
Cuisine: Southern
Ingredients: 3-4 large sweet Tennessee onions (about 2 lbs), peeled and sliced into 1/2-inch rounds (Vidalia or Walla Walla also work); 2 tablespoons unsalted butter, melted; 1/2 teaspoon salt, or more to taste; 1/4 teaspoon freshly ground black pepper; 1 1/2 cups shredded sharp cheddar cheese; 1 cup shredded mozzarella cheese; 1/2 cup grated parmesan cheese; 1/2 cup mayonnaise; 1/2 cup sour cream (full-fat recommended, or Greek yogurt for tang); 1 teaspoon garlic powder (optional); 1/2 teaspoon dried thyme or parsley; Fresh chopped chives or parsley (optional garnish); Extra parmesan for sprinkling (optional garnish)

Posted on November 28, 2025

Comfort Food

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Let me set the scene for you: it’s late afternoon, and the kitchen is brimming with the sharp, sweet perfume of sliced onions mingling with melting cheese. The moment I first pulled this Savory Tennessee Onions Bake from the oven, the bubbling golden crust was almost hypnotic—so much so that my kids hovered in the doorway, drawn by the irresistible aroma. There’s this moment when the hot cheese meets the sweet onions, and it practically calls everyone to the table. Honestly, it’s the kind of comfort you can smell from down the hall.

The first time I made this casserole, I was trying to bring a taste of the South to a chilly Saturday up north—just me, a bag of sweet onions, and a stack of old family cookbooks. My grandma used to talk about “onion pies” from church potlucks when I was knee-high to a grasshopper, and I’ve always wondered if I could recreate that same magic. Let’s face it, there’s something about simple, honest ingredients coming together in a way that feels both nostalgic and new.

When I finally sliced into the Savory Tennessee Onions Bake, I paused—a forkful of steamy, cheesy goodness in hand—and just smiled. It was a quiet triumph, the kind of dish that makes you feel like you’ve unlocked a new family favorite. My husband couldn’t stop sneaking bites right off the pan (and I can’t really blame him). It’s dangerously easy, endlessly comforting, and perfect for everything from cozy weeknight dinners to brightening up your Pinterest board with a golden, cheesy glow.

I’ve tested this recipe more times than I can count—all in the name of research, of course—and every pan disappears faster than you can say “cheesy crust.” Whether you’re looking for a crowd-pleaser for family gatherings, a unique side for your next potluck, or just a new way to enjoy onions, you’re going to want to bookmark this one. It’s pure, southern comfort—and honestly, it feels like a warm hug every single time.

Why You’ll Love This Savory Tennessee Onions Bake Recipe

Quick & Easy: Comes together in under 15 minutes of prep—seriously, you’ll spend more time waiting for it to bake than putting it together. Perfect for busy weeknights or when you need a last-minute side.
Simple Ingredients: No fancy shopping lists needed—just onions, cheese, butter, and a few pantry staples you likely already have.
Perfect for Any Occasion: Whether it’s brunch, a holiday dinner, potluck, or just a cozy meal at home, this Savory Tennessee Onions Bake fits right in.
Crowd-Pleaser: Kids and adults alike rave about the gooey, golden cheese and sweet, tender onions. Even folks who claim they “don’t like onions” end up asking for seconds.
Unbelievably Delicious: The combination of sweet Tennessee onions and a crispy, cheesy crust is comfort food at its finest—so satisfying, you’ll want to make it again and again.

What makes this Savory Tennessee Onions Bake different from the rest? I use a blend of cheeses for extra depth—sharp cheddar for bite, mozzarella for stretch, and a sprinkle of parmesan for that irresistible crispy top. The onions are sliced just thick enough to hold their texture, but thin enough to melt into the cheesy goodness. I’ve tested everything from the baking dish size to the cheese ratios, and trust me: this isn’t just another casserole. It’s the best version I’ve found after plenty of trial and error (and a few cheesy disasters along the way).

This recipe isn’t just good—it’s the kind that makes you close your eyes after the first bite. The flavor is balanced, the texture is perfect, and it’s so easy that you can whip it up on a whim. Whether you’re impressing guests or turning a simple Tuesday into something special, the Savory Tennessee Onions Bake delivers every single time. It’s comfort food, but with a little bit of Southern soul and a whole lot of cheesy charm.

What Ingredients You Will Need

This recipe uses simple, wholesome ingredients to deliver bold flavor and that signature golden, cheesy crust—no fuss, just pure comfort. Most of these are pantry staples or easy to find at any grocery store, making dinner prep a breeze.

For the Onion Layer:
- 3-4 large sweet Tennessee onions (about 2 lbs / 900 g), peeled and sliced into 1/2-inch rounds (Vidalia or Walla Walla also work great)
- 2 tablespoons unsalted butter (28 g), melted (adds richness and helps the onions caramelize)
- 1/2 teaspoon salt (2.5 g), or more to taste
- 1/4 teaspoon freshly ground black pepper (1 g)
For the Cheesy Crust:
- 1 1/2 cups shredded sharp cheddar cheese (170 g) (I love Cabot or Tillamook for big flavor)
- 1 cup shredded mozzarella cheese (113 g) (adds stretch and gooeyness)
- 1/2 cup grated parmesan cheese (45 g) (for that crispy, salty top)
- 1/2 cup mayonnaise (120 g) (Duke’s is my go-to—makes the crust extra creamy and golden)
- 1/2 cup sour cream (120 g) (use full-fat for best results, or swap with Greek yogurt for tang)
- 1 teaspoon garlic powder (3 g) (optional, but highly recommended for savory depth)
- 1/2 teaspoon dried thyme or parsley (1 g) (for a touch of herbal flavor)
Optional Garnishes:
- Fresh chopped chives or parsley (brightens up the final dish)
- Extra parmesan for sprinkling (because, honestly, you can never have too much cheese)

Ingredient Tips & Substitutions:

Can’t find Tennessee onions? Use any sweet onion—just avoid strong yellow onions for best results.
For a lighter version, substitute half the mayo with plain Greek yogurt or use light sour cream.
Want to make it gluten-free? All the ingredients are naturally gluten-free (just check your mayo and sour cream labels).
Try a smoky twist by swapping cheddar cheese for smoked gouda.
Add a kick with a sprinkle of cayenne or hot sauce in the cheese mixture.

Honestly, the hardest part is not eating the cheese straight from the bowl while you prep!

Equipment Needed

Large Baking Dish (9×13-inch / 23×33 cm): Glass or ceramic both work. I’ve used everything from old Pyrex to thrift-store finds, and they all do the job.
Sharp Chef’s Knife: Essential for slicing onions into even rounds. If you’ve got a mandoline, it’ll make quick work of the slicing, but watch those fingers (learned that lesson the hard way).
Cutting Board: I like a sturdy wooden board—less slip, more control.
Mixing Bowls: One medium and one small bowl for mixing the cheese topping and melting the butter.
Measuring Cups & Spoons: For getting those cheese and cream ratios just right.
Aluminum Foil: Helps prevent over-browning during baking (you can skip if you like a deeply golden crust).
Spatula or Spoon: To spread the cheese mixture evenly over the onions.

If you don’t have a big baking dish, split the recipe into two smaller ones. And for budget-friendly options, thrift stores are goldmines for sturdy bakeware—my favorite casserole dish was $3 and has survived more meals than I can count. Just make sure your knife is sharp and your bowls are big enough for mixing (clean-up is easier, trust me).

Preparation Method

Preheat Your Oven: Set to 375°F (190°C). While it heats, melt the butter in a small bowl—either in the microwave (about 30 seconds) or on the stovetop.
Prep the Onions: Peel and slice 3-4 large sweet Tennessee onions into 1/2-inch (1.25 cm) rounds. If your eyes start watering—hold a piece of bread in your mouth. Sounds silly, but it works for me!
Arrange in Baking Dish: Layer the onion rounds evenly in your greased 9×13-inch (23×33 cm) baking dish. Aim for a single even layer—overlapping slightly is fine if you need to squeeze them in.
Season & Butter: Drizzle the melted butter over the onions. Sprinkle with salt and pepper. Toss gently in the dish to coat (I use my hands, but a spatula works if you’re fancy).
Mix Cheesy Topping: In a medium bowl, combine 1 1/2 cups (170 g) shredded cheddar, 1 cup (113 g) shredded mozzarella, 1/2 cup (45 g) grated parmesan, 1/2 cup (120 g) mayonnaise, 1/2 cup (120 g) sour cream, 1 teaspoon (3 g) garlic powder, and 1/2 teaspoon (1 g) dried thyme. Stir until well combined—should be thick, spreadable, and a little sticky.
Spread Over Onions: Dollop the cheese mixture over the onions. Use a spatula to spread evenly, covering all the onions. Don’t worry if it’s not perfectly smooth—it’ll melt and spread out on its own.
Cover and Bake: Cover the dish loosely with aluminum foil. Bake for 25 minutes. This keeps the cheese from browning too fast while the onions soften.
Uncover and Brown: Remove the foil and bake for another 15-20 minutes, until the cheesy crust is bubbly and deep golden. Watch the edges—they should be crisp but not burnt. If your oven runs hot, check after 15 minutes.
Test for Doneness: Onions should be tender (poke with a fork—they should give easily) and the cheese should be golden and slightly crisp on top.
Cool Slightly & Garnish: Let the bake stand for 5-10 minutes before serving (otherwise, it’ll be molten cheese lava!). Sprinkle with fresh chives or parsley if you like.

Troubleshooting Tips:

If the cheese isn’t browning after the full bake, pop under the broiler for 2-3 minutes—just watch closely, it can go from golden to burnt in a flash.
If your onions are still crunchy, cover with foil and bake an extra 10 minutes.
Too watery? Use firm onions and make sure to slice thick enough—sweet onions hold up better than regular yellows.

Personal note: I always make extra because leftovers are even better the next day. And don’t skimp on that cheesy topping—it’s what makes this dish pure comfort.

Cooking Tips & Techniques

I’ve learned a thing or two after making this Savory Tennessee Onions Bake more times than I care to admit. Here’s what keeps it foolproof:

Onion Thickness: Slicing onions too thin makes them disappear into mush. Stick to 1/2-inch rounds—they hold their shape and soak up all the cheesy goodness.
Cheese Matters: Use a blend for depth. Sharp cheddar gives that Southern bite, mozzarella melts smoothly, and parmesan crisps up the top. Bagged cheese is fine, but freshly shredded melts better.
Mayonnaise Magic: Don’t skip the mayo—it helps the cheese brown and adds creaminess you just can’t get from cheese alone.
Baking Strategy: Covering with foil keeps the cheese from burning before the onions are tender. Uncover for that last stretch to get a crackly, golden crust.
Multitasking: While the bake is in the oven, prep a fresh salad or slice some bread—keeps dinner moving without stress.
Troubleshooting: If you end up with watery onions, bake a little longer uncovered. If the edges over-brown, shield them with foil strips.
Personal Failures: I once used yellow onions in a pinch—too strong, not sweet enough. Lesson learned: sweet onions are worth seeking out.
Consistency: Stick to full-fat dairy for best texture. Light or fat-free options turn runny and bland (sorry, but it’s true).

My best advice? Don’t rush the browning—let the cheese get deeply golden for the most flavor. And save a sprinkle of parmesan for the last 5 minutes for extra crunch. That’s what makes folks ask for the recipe every time.

Variations & Adaptations

One of my favorite things about this Savory Tennessee Onions Bake is how easily you can make it your own. Here are a few tried-and-true twists:

Dietary Variations: For a lower-carb version, skip the mayo and use Greek yogurt instead. To make it dairy-free, swap the cheese for plant-based alternatives and use vegan mayo and sour cream.
Seasonal Swaps: In spring, add thinly sliced leeks or scallions for extra green flavor. In summer, toss in a handful of cherry tomatoes or fresh corn kernels—it brightens up the whole dish.
Flavor Twists: Add a layer of cooked bacon bits or diced ham between the onions before topping with cheese (my kids love this). Or sprinkle in a little smoked paprika or chipotle powder for a gentle heat.
Cooking Methods: Want to skip the oven? Bake in a covered grill-safe pan over indirect heat for smoky flavor. Or make individual portions in muffin tins for cute, Pinterest-worthy sides.
Allergen Substitutions: If you need egg-free, check your mayo brand—some are made with eggs, some aren’t. For nut allergies, just stick to the classic cheese blend.
Personal Favorite: I’ve tried adding sautéed mushrooms under the onions—adds a deep, earthy flavor that pairs perfectly with the sweet onions and cheese.

Don’t be afraid to experiment! Every family has their own version, and honestly, the best discoveries come from those little kitchen tweaks.

Serving & Storage Suggestions

This Savory Tennessee Onions Bake is best served hot, straight from the oven. The cheesy crust is at its crispiest, and the onions are tender but not mushy. For presentation, slice into generous squares and sprinkle with fresh herbs—chives or parsley add a nice pop of color, especially if you’re sharing on Pinterest.

Serving Ideas:

Pair with roast chicken, grilled steak, or BBQ ribs for a hearty meal.
Serve as a vegetarian main with a green salad and crusty bread.
Great as a brunch side with eggs and bacon.
Try it with a cold glass of sweet tea or a crisp lager—classic southern combos.

Storage:

Refrigerator: Cool leftovers, cover tightly, and store up to 3 days. The flavors get even richer overnight!
Freezer: Wrap portions in foil and freeze up to 1 month. Thaw overnight in the fridge for best texture.
Reheating: Warm in a 350°F (176°C) oven, covered, for 15-20 minutes. For a crisp top, uncover for the last 5 minutes. Microwave works too, but the crust won’t be as crunchy.

The cheese might separate a little after freezing, but it still tastes mighty fine. If you have leftovers, try layering them in a grilled cheese sandwich or folding into an omelet—seriously, it’s delicious.

Nutritional Information & Benefits

Each serving of Savory Tennessee Onions Bake (about 1/8th of the pan) provides roughly:

Calories: 220
Fat: 15g
Protein: 8g
Carbohydrates: 14g
Fiber: 2g

Sweet onions are rich in antioxidants, vitamin C, and prebiotic fiber—good for gut health and immunity. Using full-fat dairy adds calcium and protein, and you can easily make this gluten-free by checking your dairy labels. This recipe contains dairy and eggs (mayo), but you can substitute for vegan or allergy-friendly options as needed. From a wellness perspective, I love how this dish packs flavor and comfort without relying on heavy starches or processed ingredients. It’s hearty, satisfying, and can fit a variety of dietary needs with a few tweaks.

Conclusion

Honestly, this Savory Tennessee Onions Bake deserves a spot on every dinner table—whether you’re feeding a crowd or just looking for a little cozy comfort. It’s easy to customize, quick to prepare, and always gets rave reviews. The golden, cheesy crust and tender, sweet onions are the kind of thing you’ll crave on rainy days, busy nights, or anytime you want a dish that just feels like home.

Don’t be afraid to put your own spin on it—add bacon, swap cheeses, toss in herbs, or try a new topping. That’s the joy of home cooking, right? For me, this casserole is a reminder of southern roots, simple pleasures, and the magic of sharing good food with people you love. If you give it a try, let me know in the comments below—share your tweaks, tag me on Pinterest, or just tell me how it turned out!

Here’s to warm kitchens, cheesy crusts, and recipes worth repeating. You’ve got this!

FAQs About Savory Tennessee Onions Bake

Can I use regular yellow onions instead of sweet Tennessee onions?

You can, but the flavor will be stronger and less sweet. For the classic taste, stick with sweet onions like Vidalia or Walla Walla.

Can I make this recipe ahead of time?

Absolutely! Assemble everything up to the baking step, cover, and refrigerate for up to 24 hours. Bake when ready to serve.

Is this casserole gluten-free?

Yes, all the ingredients are naturally gluten-free. Just double-check your mayo and sour cream labels to be safe.

What can I use instead of mayonnaise?

Greek yogurt or a blend of sour cream and cream cheese works well. The texture will be slightly different but still delicious.

Can I freeze leftovers?

Yes! Wrap tightly and freeze for up to a month. Thaw in the fridge and reheat in the oven for best results.