Masters of kitchen
Imagine sweet Vidalia onions, bathed in butter, bubbling under a blanket of melted cheese. That’s the magic of Tennessee Onions.
Tennessee Onions are a Southern comfort food staple—a simple yet unbelievably flavorful side dish that transforms humble ingredients into something irresistible. This baked onion casserole is all about sweet onions, thinly sliced and generously seasoned, then smothered in cheese and butter before baking until golden and bubbly.
So, why are they called Tennessee onions? The name pays homage to the Southern state where this cozy casserole became a beloved potluck and holiday side. Though onions are used in dishes across the U.S., this cheesy, buttery, oven-baked version captures the heart of Tennessee-style cooking—big on comfort, easy on effort, and perfect for feeding a crowd.
And the best part? You only need a few basic ingredients, but the result is pure Southern bliss on a plate.
Why Everyone Loves This Southern Classic
There’s something deeply satisfying about a dish that’s simple, affordable, and downright delicious. Tennessee Onions hit all the right notes. With a handful of ingredients—onions, cheese, butter, and a few seasonings—you get a side dish that’s rich, savory, and melt-in-your-mouth tender.
This dish is a go-to at Southern barbecues, Thanksgiving dinners, and neighborhood potlucks. It pairs beautifully with grilled meats, holiday roasts, or even burgers off the backyard grill. And because it’s naturally gluten-free and vegetarian, it’s a side that just about everyone can enjoy.
Whether you’re hosting a Sunday dinner or just want something indulgent for your weeknight table, Tennessee Onions deliver maximum flavor with minimal fuss.
Bold Tip: Use sweet onions like Vidalia for the best flavor—they mellow beautifully as they bake, turning soft, sweet, and nearly caramelized.
Ingredients Breakdown: What Makes Them So Good
What makes Tennessee Onions more than just onions and cheese? It’s all in the details. Here’s what makes this dish shine:
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Sweet Onions (like Vidalia)
These aren’t your average onions. Vidalias are low in sulfur, which gives them a gentle sweetness that’s perfect for baking. They soften beautifully in the oven, releasing their natural sugars without becoming overpowering. -
Cheese Trio: Swiss, Mozzarella, Cheddar
The classic combo includes Swiss for nuttiness, mozzarella for stretch, and cheddar for that sharp, tangy kick. Together, they melt into a rich, gooey topping that’s hard to resist. -
Butter & Seasonings
Slices of butter melt over the onions while they bake, creating a silky base of flavor. Salt, black pepper, garlic powder, and a pinch of thyme elevate the natural sweetness of the onions. These spices bring balance and just the right hint of savory. -
Optional Upgrades
Want to kick it up a notch? Add a dash of Worcestershire sauce, chopped herbs, or a pinch of crushed red pepper for heat. A sprinkle of Parmesan or a drizzle of cream can also add richness.
Tennessee Onions prove that you don’t need fancy ingredients to make something unforgettable—just the right ones, layered with care.
How to Make Tennessee Onions: Step-by-Step
Ready to bring this cheesy, savory dish to life? Follow this simple step-by-step guide:
Step 1: Preheat and Prep
Start by preheating your oven to 350°F (175°C). Lightly butter a 9×13-inch baking dish or coat it with nonstick spray. This keeps the onions from sticking and helps develop that golden, bubbly crust.
Step 2: Slice the Onions
Use 3–4 large sweet onions, such as Vidalia, and slice them into ¼-inch thick rings. Try to keep the slices even so they cook uniformly. A mandoline makes this step super quick, but a sharp knife works just fine.
Step 3: Layer & Season
Arrange the onion slices evenly in the baking dish, separating the rings as you go. Then sprinkle salt, black pepper, garlic powder, and dried thyme over each layer. Don’t be shy—seasoning each layer ensures balanced flavor in every bite.
Step 4: Add Butter Slices
Cut ½ cup of butter into small pats and scatter them evenly over the onions. As it melts, the butter soaks into the layers, helping to tenderize the onions and deepen their flavor.
Step 5: Top with Cheese
Generously sprinkle a mix of shredded Swiss, mozzarella, and cheddar cheese over the top. You want a thick, cheesy layer that completely covers the onions.
Pro Tip: Use freshly shredded cheese rather than pre-bagged—it melts smoother and has a better taste.
Step 6: Bake to Perfection
Cover the dish loosely with foil and bake for 30–35 minutes. Then, uncover and bake another 10–15 minutes until the cheese is golden and bubbling.
Want a little extra crisp on top? Pop it under the broiler for 2–3 minutes—just watch it closely to avoid burning.
The result? Soft, caramelized onions with gooey cheese and buttery flavor in every bite.
Flavor Variations and Delicious Twists
Tennessee Onions are delicious as-is, but here are some ways to make them your own:
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Add Bacon Crumbles: Sprinkle cooked bacon on top before baking for a smoky twist.
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Breadcrumb Crunch: Add panko or seasoned breadcrumbs in the last 10 minutes for a crispy topping.
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Make it Spicy: Thinly sliced jalapeños or a splash of hot sauce bring the heat.
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Gourmet Upgrade: Use Gruyère or smoked gouda for a more sophisticated flavor profile.
What to Serve with Tennessee Onions
Tennessee Onions may be a side dish, but they can steal the spotlight when paired just right.
They’re incredible with grilled meats—think steak, BBQ chicken, or pork chops. That gooey, cheesy topping complements smoky flavors beautifully. They also pair well with holiday mains like glazed ham, roasted turkey, or even meatloaf.
For a full-on Southern feast, serve them alongside cornbread, mashed potatoes, and slow-cooked green beans. They bring just the right amount of richness to balance the plate.
Want to get creative? Use Tennessee Onions as a savory topping. They’re amazing spooned over burgers, hot dogs, or baked potatoes. Try layering them inside a grilled cheese or even a breakfast sandwich for a sweet and cheesy twist.
These onions are so versatile, you’ll find yourself reaching for them again and again—from backyard cookouts to Thanksgiving spreads.
Make-Ahead Tips & Storage Info
One of the best things about Tennessee Onions? They’re incredibly make-ahead friendly.
You can prep the dish 1 day in advance—just slice the onions, layer everything, cover, and refrigerate. When you’re ready to bake, let the dish come to room temperature for about 20 minutes to ensure even cooking.
Got leftovers? Store them in an airtight container in the fridge for up to 4 days. Reheat in the oven at 325°F until warmed through. Avoid microwaving if possible—it can make the onions rubbery and the cheese oily.
Freezing isn’t recommended for this dish. Onions tend to get watery and lose their pleasant texture when thawed.
With just a little planning, you can enjoy this Southern favorite without any last-minute stress.
Why Sweet Onions Work Best (The Science)
There’s real science behind why sweet onions are the go-to for Tennessee Onions.
Sweet varieties like Vidalia, Walla Walla, or Maui have lower sulfur content, which means they don’t have that harsh bite that regular yellow onions sometimes do. When baked, they mellow and soften, releasing natural sugars that enhance their flavor.
That sweetness pairs perfectly with savory elements like butter, cheese, and herbs. As the onions cook, they caramelize slightly, becoming tender and rich without turning bitter.
Among sweet onions, Vidalias are king. Grown in Georgia, they’re known for their delicate flavor and high moisture content. Walla Walla onions (from Washington) and Maui onions (from Hawaii) are excellent substitutes if Vidalias aren’t in season.
Want the best bake? Look for onions that feel heavy for their size (a sign of high moisture) and store them in a cool, dry place until ready to use.
Bottom line: Sweet onions don’t just work—they shine.
Tennessee Onions for Holidays, BBQs & Potlucks
Whether it’s a holiday table or a summer cookout, Tennessee Onions are made for sharing.
They’re easy to double or triple for a big group. Just grab a larger baking dish—or split into two—and layer as usual. Because they’re hands-off once they hit the oven, they’re great when you have other dishes to juggle.
These onions are a standout on a Thanksgiving spread, nestled between turkey and stuffing, or as a Fourth of July BBQ side with grilled ribs and corn on the cob.
Hosting a buffet-style event? Keep Tennessee Onions warm in a crockpot on low heat after baking. They’ll stay cheesy and scoopable for hours.
It’s one of those dishes people try “just a spoonful” of… and then come back for seconds.
FAQs
What are Tennessee onions made of?
Tennessee Onions are a simple casserole made with sweet onions, butter, cheese, and seasonings like garlic powder and thyme. That’s it—just pantry basics that come together in the oven for something rich and comforting.
Are Tennessee onions spicy?
Not at all. They’re mild, slightly sweet, and cheesy. But if you like heat, you can always add jalapeños or a few dashes of hot sauce to spice things up.
Can I use regular yellow onions instead?
Yes, you can—but the flavor will be stronger and more pungent. Sweet onions like Vidalia are preferred because they mellow as they bake and don’t overpower the dish.
Can you make Tennessee onions in the air fryer?
You can make a small batch in the air fryer if you have a baking-safe dish that fits. Lower the temperature slightly and check frequently to make sure the cheese doesn’t burn. It’s quick, but ovens yield the best texture overall.
What cheese is best for Tennessee onions?
A blend of Swiss and mozzarella melts beautifully, while sharp cheddar adds bold flavor. Feel free to mix it up—Gruyère, gouda, or Monterey Jack all work well too.
Final Thoughts: A Simple Southern Staple
Tennessee Onions are one of those no-fuss, big-flavor dishes that stick with you. Whether you’re hosting a crowd or just want something cozy on a weeknight, this side dish checks every box: easy, affordable, and downright delicious.
It’s proof that a few good ingredients—layered with love—can create something special.
Give them a try at your next cookout or holiday meal. And if you add your own twist, like bacon or spicy cheese, drop a comment and share it—we’d love to hear how you made it your own!
Tennessee Onions
Equipment
- 9x13 inch baking dish
- Cutting board and knife
- Foil
- Cheese grater (if shredding fresh cheese)
- Oven
Ingredients
- 3 –4 large sweet onions Vidalia preferred, sliced into ¼-inch rings
- ½ cup 1 stick unsalted butter, sliced
- 1½ cups shredded Swiss cheese
- 1½ cups shredded mozzarella
- 1 cup shredded sharp cheddar cheese
- 1 tsp garlic powder
- 1 tsp salt
- ½ tsp black pepper
- ½ tsp dried thyme optional
Instructions
- Preheat oven to 350°F (175°C). Lightly butter or spray a 9x13-inch baking dish.
- Slice the onions into even ¼-inch rings and separate the layers.
- Layer the onions evenly in the dish. Season each layer with garlic powder, salt, pepper, and thyme.
- Distribute the butter slices evenly across the top of the onions.
- Top with cheese, layering Swiss, mozzarella, and cheddar generously across the surface.
- Cover with foil and bake for 30–35 minutes. Remove foil and continue baking for another 10–15 minutes, until cheese is golden and bubbling.
- Optional: Broil for 2–3 minutes for a crispier top—watch closely!
- Let sit 5–10 minutes before serving. Enjoy warm.
Notes
- Vidalia onions are ideal, but Walla Walla or Maui onions also work well.
- Freshly shredded cheese melts more smoothly than pre-shredded.
- Add bacon crumbles, breadcrumbs, or jalapeños for fun variations.
- Can be assembled a day ahead and baked fresh before serving.
- Store leftovers in the fridge up to 4 days. Reheat in the oven for best texture.
Nutrition
