The Cheapest Thanksgiving Side Dish You Can Make This Year

I’m not one to shy away from onions in my cooking. From creamy onion soup to hamburger steaks topped with onions and gravy, onions are a staple ingredient in my kitchen, as I love the extra flavor they provide when added to a recipe. As a kid, I was a picky eater who stayed away from onions in all forms, but as an adult food writer, I’ve reconsidered my position on onions and have fully embraced the crunchy vegetable as an ingredient.

When I started seeing videos about Tennessee Onions in my TikTok feed, even this onion convert felt a bit unsure. Millions of TikTokers are sharing their own takes on the dish, made with sweet Vidalia onions and lots of butter, but would a casserole dish full of sliced, cheesy onions really be that mind-blowing? Since one enthusiastic TikToker called Tennessee Onions one of her favorite side dishes, I decided to give the dish a try in my own kitchen.

What Are Tennessee Onions?

Tennessee Onions have many layers: sliced sweet onions, lots of shredded cheese, butter, and spices baked together in a 9×13-inch casserole dish until the onions are soft and flavorful. While TikTok is full of varied takes on the side dish (videos with the #TennesseeOnions hashtag have millions of views on the platform), the one consensus seems to be that it’s essential to use a sweet onion, preferably the Vidalia variety.

Chelsea Page, the interim executive director at the Vidalia Onion Committee, says Vidalia onions are a great addition to the recipe because of their “unique flavor and sweetness.”

How to Make Tennessee Onions

To make this sweetly viral dish in my own kitchen, I started with a 3-pound bag of Vidalia onions, peeling and slicing most of them into 1/4-inch thick rings. I greased my 9×13-inch baking dish and filled it to the brim with sweet onions, then I cut an entire stick of butter into thin pats and laid them over top of the onions. Butter is vital in any Tennessee Onions recipe, as it melts over the raw onions and helps them cook down and soften in the oven.

After watching many TikTok videos with different creators sharing their take on the dish, I chose my next steps based on the flavor profiles that sounded best to me. That’s the beauty of Tennessee Onions—there’s room for experimentation with the spices and types of cheese you most enjoy. I topped my butter-covered, sliced onions with sprinkles of garlic salt, freshly ground black pepper, parsley, and paprika, but you could tweak the recipe to use any spice combination that sounds good to you. Next, I sprinkled about one cup each of shredded Cheddar and mozzarella cheese on top, then finished it with about a half cup of shredded Parmesan cheese.

I compared many varying cook times and oven temperatures for baking my Tennessee Onions and assumed the longer my casserole dish baked, the softer and more delicious the onions would become. I was right. The sweet spot for my Vidalia onion casserole was baking it covered with foil for 40 minutes at 350 degrees F. I then raised the heat to 425 degrees F and baked the Tennessee Onions uncovered for another 30 minutes until the onions were soft and the cheese was lightly browned on top.

What Do Tennessee Onions Taste Like?

My onion-slicing and cheese-grating resulted in an incredibly delicious side dish that tasted like French onion soup in casserole form. The Vidalia onions became sweet and tender in the oven, and the cheeses melted perfectly, with a few caramelized bits that provided extra flavor. Savory spices like garlic salt and black pepper perfectly complemented the sweetness of the onion, and the melty butter throughout the dish gave a rich and decadent backdrop to the casserole.

What to Serve with Tennessee Onions

Along with my Tennessee Onions, I prepared country-fried cube steak with white gravy and tossed some frozen potato wedges into my air fryer. The meal felt distinctly Southern and pleased everyone at my dinner table—especially my husband, who created his take on loaded potato wedges by topping the air-fried spuds with gravy, steak, and a heaping pile of Tennessee Onions.

The casserole was buttery and cheesy, and the soft, butter-braised texture of the sweet Vidalia onions would be the perfect accompaniment to a holiday dinner—be in Thanksgiving turkey or Christmas ham. What’s more, since onions are the main ingredient, it’s an economical side to add to your holiday menu.

Like many TikTok trends, creators who are sharing their love of Tennessee Onions did not steer me in the wrong direction. The toasty, oniony dish will remain in my side dish rotation. Since the friends and family I asked about the dish had never heard of it, I’m looking forward to making the tasty side for Thanksgiving and teaching the people I love about my new favorite way to eat onions.