Easy Tennessee Onion Casserole
This Tennessee Onions Casserole is a rich and cheesy Southern side dish made with sweet Vidalia onions, cheddar, smoked Gouda, and Parmesan. Perfect for cookouts, potlucks, or holiday tables, it's a comforting, golden-baked casserole that brings out the best in caramelized onions.
Ingredients
- Cooking spray
- 3 lbs Vidalia or sweet onions about 4 large, sliced into 1/4-inch rings
- 1 1/2 tsp kosher salt
- 1 tsp dry mustard powder
- 1 tsp garlic powder
- 1 tsp smoked paprika
- 1/4 tsp cayenne pepper optional
- 4 oz mild cheddar cheese shredded (about 1 cup), divided
- 4 oz smoked Gouda or cheddar cheese shredded (about 1 cup), divided
- 1 1/4 oz grated Parmesan cheese about 1/3 cup
- 4 tbsp unsalted butter diced
- 2 tbsp fresh chopped parsley optional, for garnish
Instructions
- Preheat oven to 350ºF and coat a 9x13-inch baking dish with cooking spray.
- In a large bowl, separate onion rings and toss with salt, mustard powder, garlic powder, smoked paprika, and cayenne.
- Layer half the onions in the dish, followed by half of the cheddar and Gouda.
- Add the remaining onions, top with remaining cheeses, sprinkle with Parmesan, and dot with butter.
- Cover with foil and bake for 45 minutes.
- Uncover and bake an additional 30 minutes, until golden and bubbly.
- Garnish with chopped parsley before serving (optional).
Notes
- Cheese swaps: Try Monterey Jack or Fontina for a creamier result.
- For crunch: Add crushed Ritz crackers with butter on top before the final bake.
- Add protein: Layer in cooked chicken bits for extra savory depth.
- Storage: Store leftovers in an airtight container in the fridge for up to 4 days.
- Reheating: Best reheated in the oven at 350ºF for 15–20 minutes.