Golden, bubbling, and full of flavor, Tennessee Onions are a Southern-style baked dish that transforms the humble onion into a cheesy, savory masterpiece. Sliced thick and layered in a casserole dish, these onions are roasted until tender, then smothered in a mix of melty cheeses and a touch of seasoning that brings out their natural sweetness. It’s the kind of comfort food that quietly steals the show, perfect alongside grilled meats, tucked into a holiday table, or served as the star of a cozy weeknight dinner.

Their simplicity is part of the charm—this dish requires minimal prep but delivers maximum flavor. With crispy caramelized edges, gooey cheese, and herbs adding a touch of freshness, Tennessee Onions are a hidden gem that deserves a permanent spot in your rotation. Whether you’re a lifelong onion lover or just looking for a unique side dish idea, this is one to bookmark.

Ingredients for Tennessee Onions

4–5 large sweet onions (like Vidalia or Walla Walla)
1 ½ cups shredded mozzarella cheese
1 cup shredded cheddar cheese
½ cup grated parmesan cheese
4 tbsp unsalted butter, melted
1 tsp garlic powder
1 tsp onion powder
½ tsp paprika
Salt and black pepper to taste
Fresh thyme (optional, for garnish)
Non-stick cooking spray or olive oil for greasing the dish

Step 1: Prep the Onions

Preheat your oven to 375°F (190°C). Peel the onions and slice them into thick rings, about ½ inch wide. Separate the rings slightly but keep the general shape intact for a beautiful presentation.

Step 2: Arrange in Baking Dish

Lightly grease a 9×13-inch baking dish with cooking spray or a bit of olive oil. Place the onion slices flat into the dish in a single layer, fitting them snugly side by side.

Step 3: Season Generously

Drizzle the melted butter evenly over the onions. Sprinkle garlic powder, onion powder, paprika, salt, and pepper all over the top. This is what helps bring out that rich, savory flavor as they roast.

Step 4: Add the Cheese

Cover the onions with a layer of shredded mozzarella, followed by cheddar, then finish with parmesan. The blend of cheeses will melt beautifully and create a bubbly, golden crust on top.

Step 5: Bake Until Golden

Place the dish in the preheated oven and bake for 35–40 minutes, or until the onions are tender and the cheese is melted, bubbly, and golden brown around the edges.

Step 6: Garnish and Serve

Remove from the oven and let cool for a few minutes. Garnish with fresh thyme leaves if desired. Serve warm as a side dish or even as a savory main for veggie lovers.

Storage Instructions

Tennessee Onions store surprisingly well, making them a great make-ahead or leftover option. Let the dish cool completely, then transfer to an airtight container or cover the baking dish tightly with foil or plastic wrap. Store in the refrigerator for up to 4 days.

To reheat, place a portion in the oven at 350°F (175°C) for about 10–15 minutes or microwave individual servings for 1–2 minutes. If reheating a large portion, consider covering with foil to retain moisture and avoid over-browning the cheese.

Freezing is not recommended, as onions can become mushy and lose their texture after thawing.

Estimated Nutrition

Per serving (based on 6 servings):

Calories: 220
Fat: 15g
Saturated Fat: 9g
Carbohydrates: 12g
Sugar: 7g
Protein: 10g
Fiber: 2g
Sodium: 300mg

Note: Values may vary slightly based on cheese type and portion size.

Frequently Asked Questions

What type of onions work best?

Sweet onions like Vidalia or Walla Walla are ideal, but yellow onions can work in a pinch—they’ll just have a stronger flavor.

Can I make this dish ahead of time?

Yes! Assemble everything in the baking dish, cover tightly, and refrigerate for up to 24 hours before baking.

Is it possible to make it vegetarian?

Absolutely—it’s already vegetarian as written. Just be sure your cheeses are made without animal rennet if that’s a concern.

What can I serve with Tennessee Onions?

They pair wonderfully with grilled meats, roasted chicken, or as a side to barbecue. They’re also great with a simple green salad or crusty bread.

Can I add breadcrumbs on top?

Yes! For an extra crispy top, sprinkle panko breadcrumbs mixed with a little melted butter before baking.

How do I avoid soggy onions?

Make sure to slice them thickly and don’t overcrowd the dish—this allows the onions to roast rather than steam.

Can I use different types of cheese?

Definitely. Try Gruyère for a nutty touch or pepper jack if you like a kick of spice.

Are Tennessee Onions gluten-free?

Yes, this dish is naturally gluten-free—just double-check that your cheese brands are GF-certified if you’re highly sensitive.

Tennessee Onions

Author: Zoe Adelson
Total Time: 14 minute
Yield: Serves 6

Print Recipe

Description

If you’re craving something warm, cheesy, and soul-satisfying, Tennessee Onions are calling your name. This comforting Southern dish turns simple sweet onions into a golden, cheesy, bubbling delight that’s perfect for weeknight dinners, BBQ sides, or holiday spreads. With minimal prep and a big flavor payoff, it’s one of those easy recipes you’ll keep coming back to.

Instructions

Preheat oven to 375°F (190°C).
Peel onions and slice into thick rings (about 1/2 inch). Keep rings mostly intact.
Grease a 9×13-inch baking dish and arrange onion slices in a single, snug layer.
Drizzle melted butter over the onions.
Sprinkle with garlic powder, onion powder, paprika, salt, and pepper.
Top evenly with mozzarella, cheddar, and parmesan cheese.
Bake for 35–40 minutes, until onions are tender and cheese is golden and bubbly.
Let cool slightly, garnish with fresh thyme, and serve warm.

Prep Time: 10 minutes
Cook Time: 35–40 minutes
Category: Side Dish