SPREAD LOVE

Tennessee Onions: The Cheesy Baked Side Dish Better Than Onion Rings

Name: Tennessee Onions
Prep time: 15 min
Cook time: 35 min
Total time: 50 min
Cuisine: Southern
Ingredients: 3 large sweet onions (Vidalia or Walla Walla), peeled and thinly sliced; 8 tablespoons unsalted butter, divided; 1 teaspoon olive oil; 1/2 teaspoon salt, plus more to taste; 1/4 teaspoon freshly ground black pepper, plus more to taste; 1/2 teaspoon garlic powder; 1/4 teaspoon onion powder; 1/4 teaspoon smoked paprika; 1/4 cup all-purpose flour; 2 cups whole milk, warmed; 1 cup heavy cream; 8 ounces mozzarella cheese, freshly shredded or cubed; 4 ounces provolone cheese, freshly shredded or thinly sliced; 1/2 cup grated Parmesan cheese, divided; 1 cup Panko breadcrumbs; 2 tablespoons fresh parsley, chopped (optional, for garnish)

There’s something comforting and a little indulgent about soft, sweet onions smothered in melty cheese and crowned with a crunchy breadcrumb top — this is what Tennessee Onions delivers. Beautifully simple to prepare yet rich enough to steal the show at any meal, it’s a Southern-style baked casserole that transforms humble onions into a luscious, crowd-pleasing side. If you love dishes with big onion flavor and creamy texture, don’t miss these; and if you enjoy similar cheesy onion ideas, try cheesy French onion meatballs for another fun twist.

Why make this recipe
If you’re tired of the same fried sides and want something that feels homey but a little elevated, this recipe is perfect because it swaps greasy frying for creamy, oven-baked comfort. Sweet onions become tender and flavorful, a silky cheese sauce wraps every slice, and a buttery Panko crust provides the crunch taken to the next level — all without standing over a fryer. It’s also endlessly versatile: serve it as a side for weeknight chicken, use it as a vegetarian main, or bring it to potlucks where it will vanish fast.

Step-by-Step Guide to Making Tennessee Onions

Preheat Oven and Prepare Dish
Preheat your oven to 375°F (190°C). Grease a 9×13-inch baking dish thoroughly with butter or non-stick spray so the casserole won’t stick in the corners.
Slice Onions
Peel 3 large sweet onions (Vidalia or Walla Walla are ideal) and slice them into 1/4-inch-thick rings or half-moons. Aim for even thickness so they cook uniformly; separate the rings or lay the half-moons loosely so they don’t clump too tightly.
Sauté Onions
In a large, deep skillet or Dutch oven, melt 3 tablespoons of unsalted butter with 1 teaspoon of olive oil over medium heat. Add the sliced onions and toss them to coat in the butter and oil.
Season and Soften Onions
Sprinkle the onions with 1/2 teaspoon salt, 1/4 teaspoon freshly ground black pepper, 1/2 teaspoon garlic powder, 1/4 teaspoon onion powder, and 1/4 teaspoon smoked paprika. Cook, stirring occasionally, for about 15–20 minutes. You want the onions to be translucent, tender, and fragrant but not heavily caramelized — their sweet, slightly soft texture is what lets them soak up the cheese sauce. Transfer the softened onions to a large mixing bowl and set aside.
Prepare the Roux
Return the same skillet to medium heat and melt the remaining 3 tablespoons of unsalted butter. Sprinkle in 1/4 cup all-purpose flour and whisk continuously for 1–2 minutes so the raw flour flavor cooks off and you form a smooth, pale roux.
Whisk in Liquids
Gradually whisk in 2 cups of warmed whole milk, adding a little at a time and ensuring it’s fully incorporated before adding more to prevent lumps. Once the milk is smoothly combined, slowly whisk in 1 cup heavy cream. Keep whisking as the sauce simmers gently; it should begin to thicken in 3–5 minutes and coat the back of a spoon.
Introduce Cheeses
Reduce heat to low. Stir in 8 ounces freshly shredded or cubed mozzarella, 4 ounces provolone (shredded or thinly sliced), and half (1/4 cup) of the grated Parmesan cheese. Blend until the cheeses melt into a smooth, velvety sauce — do not let it boil vigorously once the cheese is added. Taste and add more salt or pepper if needed.
Combine Onions and Sauce
Pour the creamy cheese sauce over the sautéed onions in the mixing bowl. Gently fold until every piece of onion is thoroughly coated in the sauce. The goal is an even distribution so each bite is creamy and cheesy.
Prepare Panko Topping
In a small bowl, mix 1 cup Panko breadcrumbs with the remaining 1/4 cup grated Parmesan. Melt 2 tablespoons unsalted butter and drizzle over the Panko-Parmesan mix; toss with a fork so everything is evenly moistened and buttered.
Layer into Baking Dish
Spoon the onion-and-cheese mixture into the prepared 9×13-inch baking dish and spread into an even layer.
Apply Crispy Topping
Evenly sprinkle the buttered Panko-Parmesan mixture over the top, covering the surface to ensure a golden, crunchy crust when baked.
Bake to Golden Perfection
Place the baking dish in the preheated oven and bake for 30–35 minutes. You’ll know it’s done when the sauce is bubbling at the edges and the Panko topping is a deep golden brown. If the topping is browning too quickly, loosely tent the dish with foil for the remainder of the bake time.
Rest Before Serving
Remove the dish from the oven and let it rest 10–15 minutes. This resting time helps the sauce thicken slightly, making it easier to portion and enhancing flavor integration.
Garnish and Serve
Just before serving, sprinkle 2 tablespoons chopped fresh parsley for color and a hint of freshness. Serve warm straight from the baking dish.

Ingredients

3 large (about 2.5–3 pounds) sweet onions (Vidalia or Walla Walla), peeled and thinly sliced
8 tablespoons unsalted butter, divided
1 teaspoon olive oil
1/2 teaspoon salt, plus more to taste
1/4 teaspoon freshly ground black pepper, plus more to taste
1/2 teaspoon garlic powder
1/4 teaspoon onion powder
1/4 teaspoon smoked paprika
1/4 cup all-purpose flour
2 cups whole milk, warmed
1 cup heavy cream
8 ounces mozzarella cheese, freshly shredded or cubed
4 ounces provolone cheese, freshly shredded or thinly sliced
1/2 cup grated Parmesan cheese, divided
1 cup Panko breadcrumbs
2 tablespoons fresh parsley, chopped (optional, for garnish)

Best Way to Store Tennessee Onions

Refrigerator: Cover the baking dish tightly with aluminum foil or transfer leftovers to an airtight container. Store for up to 3–4 days at 40°F (4°C) or below.
Freezer: For longer storage, portion into freezer-safe containers and freeze for up to 2 months. Thaw overnight in the refrigerator before reheating.
Reheating: Reheat individual portions in a 350°F (175°C) oven for 10–15 minutes until warmed through and the topping is crisp. For microwave reheating, cover loosely and heat in short intervals, but expect the topping to soften.

Serving Suggestions for Tennessee Onions
Tennessee Onions is an indulgent accompaniment that pairs wonderfully with savory mains and can act as a satisfying vegetarian entree. Here are several ways to present it:

Classic pairing: Serve alongside roasted or grilled chicken, pork chops, or meatloaf. The creamy onion casserole slices complement simple proteins and add a decadent contrast to smoky or herb-forward meats.
With steaks or barbecue: Place a generous spoon of Tennessee Onions next to a grilled steak or smoked ribs. The richness of the cheese and the sweet onion flavor balances the char and spice of BBQ.
As a vegetarian main: Offer it with a crisp green salad, crusty bread, or a bowl of herby quinoa for a complete meat-free meal. Top with extra parsley and a squeeze of lemon to brighten the dish.
Potluck favorite: Transport this casserole in its baking dish; it reheats well and is easy to serve family-style. It’s a crowd-pleaser at holidays and weeknight gatherings alike.
Brunch twist: Spoon Tennessee Onions onto toasted sourdough or a flaky biscuit and top with a fried egg for a savory brunch option.

Tips to Make Tennessee Onions

Use sweet onions: Vidalia or Walla Walla deliver the right balance of sweetness and texture; yellow onions will work, but expect a sharper flavor.
Warm your dairy: Warming the milk and cream before whisking into the roux cuts down lumps and keeps the sauce silky.
Watch the heat when melting cheese: Keep the sauce on low once you add cheese to avoid graininess from overheating.
Crisp the topping last: If you want extra crunch, broil the Panko topping for 1–2 minutes at the end — watch closely to prevent burning.
Rest before serving: Don’t skip the 10–15 minute rest; the sauce sets and the casserole becomes easier to slice.

Variations

Bacon and herbs (bullet): Crisp 6 slices of bacon until crunchy, crumble, and fold into the onion-cheese mixture before baking. Stir in 1–2 tablespoons chopped fresh thyme or rosemary for an herby, smoky twist.
Lighter version (paragraph): To reduce richness, substitute half-and-half for the heavy cream and use 2% milk instead of whole milk. Reduce the total cheese by about a third and replace some of the Panko with finely crushed whole-wheat crackers for a slightly lighter, still-satisfying casserole.

FAQs
Q: How do I prevent a grainy cheese sauce?
A: Keep the heat low once you add cheese and stir gently until melted. Use freshly shredded cheeses instead of pre-shredded blends, which contain anti-caking agents that can affect texture.

Q: Can I make Tennessee Onions ahead of time?
A: Yes — assemble the casserole, cover tightly, and refrigerate for up to 24 hours before baking. Add a few extra minutes to the bake time if it’s very cold from the fridge.

Q: Is there a gluten-free option?
A: Replace the all-purpose flour with a 1:1 gluten-free flour blend for the roux and swap Panko breadcrumbs for gluten-free breadcrumbs or crushed gluten-free crackers.

What if my onions start to brown while softening?

If they begin to color significantly during the sauté, reduce the heat and add a splash of water to slow browning. The recipe calls for tender but not caramelized onions to keep that bright sweet flavor.

Can I use different cheese combinations?

Absolutely: Swiss or Gruyère add a nutty depth, while sharp Cheddar gives a tangier bite. Just be mindful of melting properties — avoid super hard aged cheeses without blending them with a good melting cheese.

Conclusion
Tennessee Onions is a deceptively simple casserole that converts ordinary sweet onions into a crowd-pleasing, cheesy masterpiece. Whether you serve it as a show-stealing side at a holiday table or a comforting weeknight accompaniment, the contrast of silky cheese sauce and crunchy Panko topping makes this dish memorable. For a classic recipe origin and additional tips, see this detailed version at Tennessee Onions Recipe | The Kitchn, and for another delicious take on this onion-forward comfort food, check out Tennessee Onions | 12 Tomatoes.