Tennessee Onions Casserole Recipe: Sweet Onions, 3 Cheeses by 30Seconds Food

Tennessee Onions Casserole Recipe: Sweet Onions, 3 Cheeses

Tennessee onions are simply sweet onions (think Vidalia) baked with garlic and lots of cheese. This easy Tennessee onion casserole recipe can be served with any protein or even used on burgers.

The sliced onions are put into a casserole dish and seasoned with garlic salt or garlic powder and black pepper, then dotted with butter and sprinkled with shredded mozzarella and Parmesan cheese. If you use garlic powder, you may want to add a little salt. But be careful because the cheeses are already salty. The onions are baked in the oven for about 30 minutes or until hot, melted and bubbly. Mmm! 

Chopped fresh herbs can be added for freshness. After one bite of this easy onion casserole recipe, onion lovers will be jonesing for the next.

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Cuisine: American
Prep Time: 10 minutes
Cook Time: 30 minutes
Total Time: 40 minutes

Servings: 6


  • 2 - 3 whole sweet onions, sliced into 1/4- to 1/2-inch rings
  • 4 tablespoons butter, cut into small pieces
  • garlic salt or garlic powder, to taste
  • 1 cup shredded sharp cheddar cheese
  • 1 cup shredded mozzarella
  • 1/2 cup grated Parmesan 

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Recipe Notes

  • Instead of mozzarella, try using gruyere, Swiss, fontina, Monterey jack or your favorite cheese.
  • Storing onions in the refrigerator helps reduce the tears that can come when chopping or slicing them.

Here's how to make it:

  1. Spray a 13x9-inch baking pan with nonstick cooking spray. Arrange the onions in the pan. Sprinkle the onions with garlic salt or garlic powder and black pepper, to taste. Dot the top with the butter. Sprinkle with the cheeses.
  2. Bake in a preheated 350-degree F oven for about 30 minutes or until cheese is bubbly and casserole has started to brown. 

Recipe cooking times and servings are approximate. To ensure image quality, we may occasionally use stock photography. Need to convert cooking and baking measurements? Here are some kitchen conversion charts. Here's how to submit your recipes to 30Seconds.

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Elisa Schmitz
OMGoodness, I want this on a burger right now! #yum
What a fun idea as a topping or side dish 😋
Melissa Vickers
I tried this last night! It was SOOOO good--almost like homemade mac & cheese, only with sweet onions. And hard as it is for me to actually follow a recipe as written, I did for this one, other than cutting it in half. I'll be making this one again--soon!
Elisa Schmitz
So glad you enjoyed this recipe, Melissa Vickers ! I am LOL that you actually followed the recipe this time. Love your creative cooking!

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