Tennessee Onions Recipe

This old-fashioned onion casserole is unlike any side dish you've had before.

Julia is an experienced cook with a demonstrated history of working in the publishing industry. She is skilled in catering, food & beverage, event planning, and menu development. She tests and develops recipes in the DotDash Meredith Test Kitchen for Southern Living.

Onions don't get the credit they deserve. They're the backbone of soups, casseroles, and pasta dishes. They're also wonderful chopped or sliced and served raw on salads, sandwiches, even burgers.

But even the most ardent onion fan has probably never heard of Tennessee Onions.

This onion casserole is made with a handful of simple ingredients: onions, cheese, and butter mainly. Some herbs are added to boost the flavor of the final dish and the rich sauce that forms in the pan as the onions melt and tenderize.

The key to this dish is, obviously, the onions. But not just any onions will do. You need sweet onions, and more specifically, you need sweet Vidalia onions if you can find them.

The Georgia-grown sweet onions are beloved for their naturally sweet taste. They still have a bit of bite, like any onion should, but they're not pungent and assertive. Farmers in Georgia credit the unique soil of the 20-county growing region, centered around, you guessed it, Vidalia, Georgia, for the unique flavor.

So why do Tennessee Onions use Georgie onions? We're really not sure, but we're going to eat it anyway.

Melty cheeses—we use smoked gouda and mild Cheddar—get a bit crispy and blend into the herbs and butter to create a sauce that you better not leave behind. The final dish is a cheesy, tangy-sweet scoop of tender onion slices with browned bits of cheese.

Caitlin Bensel; Food Stylist: Torie Cox

This casserole is straightforward, but that doesn't mean there aren't some handy tips to make the final dish better.

We aren't sure whether to call these onions a side dish or a condiment. So really, we'll treat them as both.

A scoop of these at a potluck or barbecue will be welcomed by all, but we also want to eat them on burgers, atop grilled chicken or steak, or even in between slices of bread for an onion-rich grilled cheese.

Cooking spray

2 1/2 lb. sweet onions (about 3 large onions), sliced crosswise into 1/4-in.-thick slices and separated into rings

1 tsp. dried thyme

1 tsp. dried parsley flakes

1 tsp. garlic salt

1/2 tsp. dried oregano

1/2 tsp. dry mustard

1/4 tsp. cayenne pepper

1/4 cup salted butter, cut into 1/4-in.-thick pieces

4 oz. mild Cheddar cheese, shredded (about 1 cup)

4 oz. smoked Gouda cheese, shredded (about 1 cup)

Preheat oven to 350°F. Coat a 13- x 9-inch baking dish with cooking spray.

Gather your ingredients.

Caitlin Bensel; Food Stylist: Torie Cox

Place onions in a large bowl. Sprinkle with thyme, parsley, garlic salt, oregano, mustard, and cayenne pepper; toss gently to coat.

Caitlin Bensel; Food Stylist: Torie Cox

Arrange evenly in prepared baking dish.

Caitlin Bensel; Food Stylist: Torie Cox

Arrange butter evenly over onions, and sprinkle with Cheddar and Gouda.

Caitlin Bensel; Food Stylist: Torie Cox

Cover with aluminum foil, and bake in preheated oven until onions are soft and sides are bubbly, about 40 minutes.

Caitlin Bensel; Food Stylist: Torie Cox

Remove foil. Bake at 350°F until top is golden, about 30 minutes.

Caitlin Bensel; Food Stylist: Torie Cox