Quick Easy Tennessee Onions Recipe

I stumbled on Tennessee Onions during a potluck season when I needed something simple but crowd-pleasing. The combination of sweet onions, three kinds of cheese, and a hint of Cajun heat turned into one of those recipes I now make on repeat.

The beauty of this dish is how the onions soften and caramelize under all that melted cheese. Every bite delivers tender sweetness with a savory, slightly spicy kick that pairs well with just about any main course.

What makes this Tennessee Onions recipe a keeper for years to come

I love how forgiving this recipe is when you’re short on time or ingredients. You can prep everything in under ten minutes, and the oven does the rest while you focus on other dishes.

The three-cheese blend creates layers of flavor that feel indulgent without being heavy. Sweet onions balance the richness, and the Cajun seasoning adds just enough warmth to keep things interesting.

This side works for weeknight dinners, holiday spreads, or casual get-togethers. I’ve served it alongside grilled chicken, roasted beef, and even as part of a vegetarian spread, and it always gets requests for the recipe.

Looking for more simple veggie sides? My Easy Roasted Cauliflower Recipe brings the same hands-off approach with crispy edges, and the Crispy Garlic Parmesan Zucchini delivers bold flavors that pair perfectly with these Tennessee Onions.

Everything you need for the perfect Tennessee Onions

• 3 sweet onions, sliced into 1/4-inch slices
• 1 1/2 teaspoons Cajun seasoning (adjust to taste)
• 1 teaspoon garlic powder
• 4 tablespoons butter, cut into 6 slices
• 1 cup shredded Cheddar cheese
• 1 cup shredded mozzarella cheese
• 1/2 teaspoon dried oregano
• 1/2 cup grated Parmesan cheese

I use Vidalia or Walla Walla onions when they’re in season, but any sweet onion variety works well. For the Cajun seasoning, start with the recommended amount and add more if you prefer extra heat.

If you don’t have Cajun seasoning on hand, a mix of paprika, cayenne, garlic powder, and black pepper makes a solid substitute.

The butter adds richness as it melts into the onions, so don’t skip it. I prefer freshly shredded cheese over pre-shredded for better melting, but either works in a pinch.

My Method for Tennessee Onions

1. Preheat your oven to 350°F (175°C) and grab a 9×13-inch casserole dish.
2. Arrange half of the sliced onions in an even layer on the bottom of the dish. Sprinkle half the Cajun seasoning and half the garlic powder over the onions. Repeat with the remaining onions, seasoning, and garlic powder to create two seasoned layers.
3. Distribute the butter slices evenly across the top of the onions. The butter will melt and seep down into the layers as it bakes, adding richness throughout.
4. Sprinkle the Cheddar and mozzarella cheeses evenly over the onions and butter. Add the oregano over the cheese layer, then finish with the grated Parmesan on top.
5. Bake uncovered for about 35 minutes, until the onions are tender when pierced with a fork and the cheese is melted, bubbly, and golden brown around the edges. The top should have some caramelized spots for extra flavor.
6. Let the dish rest for 5 minutes before serving. This allows the cheese to set slightly and makes it easier to scoop out portions.

My go to methods for Tennessee Onions success

Slice the onions evenly so they cook at the same rate. Thicker slices take longer to soften, while thinner ones can turn mushy, so aim for a consistent 1/4-inch thickness.

If you want a little crunch on top, add a handful of panko breadcrumbs mixed with melted butter during the last 10 minutes of baking. This creates a contrast with the tender onions underneath.

For a milder version, reduce the Cajun seasoning to 1 teaspoon or swap it for Italian seasoning. You can also add cooked crumbled sausage or diced mushrooms between the onion layers for a heartier dish.

When I usually serve my Tennessee Onions

I make this when I need a side that holds up well on a buffet table or potluck spread. The dish stays warm for a while and doesn’t lose its appeal as it sits.

It pairs especially well with grilled meats, roasted chicken, or even a simple steak. I’ve also served it alongside scrambled eggs for a savory breakfast twist that feels a little indulgent.