This Easy Tennessee Onions Recipe transforms the humble sweet onion into an unforgettable, cheesy side dish. With just a handful of ingredients, you can create a bubbly, golden-brown casserole that’s pure comfort in a baking dish. It’s one of those veggie dishes that even the most skeptical eaters will adore.
My dad, James, wasn’t a man of many words, but he showed his love through his cooking. On Sundays, he’d make these baked onions alongside his roast. Watching the cheese turn golden with him was our quiet, shared kitchen ritual.
Why This Recipe Feels Like a Hug in a Dish
- Simple & Flavorful: This dish relies on the natural sweetness of the onions, enhanced by simple herbs and three kinds of cheese.
- Crowd-Pleaser: A perfect side for potlucks, holidays, or a simple Sunday dinner.
- Versatile: Pairs wonderfully with roasted meats, grilled chicken, or steak.
- Quick Prep: Takes only a few minutes to assemble before it goes into the oven.
The One Pan I Always Reach For
My Favorite 9×13-inch Baking Dish
A sturdy ceramic or glass baking dish is my go-to for this recipe, as it bakes this onion casserole evenly every time.
Gathering Your Ingredients
- 3–4 large sweet onions (like Vidalia)
- 4 tablespoons unsalted butter, melted
- 1 teaspoon garlic powder
- 1 teaspoon dried oregano
- 1 teaspoon dried thyme
- Salt and black pepper, to taste
- 1 cup shredded mozzarella cheese
- 1 cup shredded cheddar cheese
- 1/2 cup grated Parmesan cheese
- Fresh thyme sprigs, for garnish
How to Make Dad’s Famous Tennessee Onions
A Warm Welcome for Your Onions
First, preheat your oven to 375°F (190°C) and give a 9×13-inch baking dish a light coating of grease. I find getting everything ready beforehand makes the whole process feel so much calmer and more enjoyable.
Tucking the Onions into Their Dish
Next, arrange your onion slices in the prepared dish. You can overlap them in simple layers or get a little creative and roll them into pretty “roses.” Dad always just layered them, but either way is delicious!
A Little Sprinkle of Magic
Now, pour the melted butter evenly over all the onions, making sure each one gets a little bit. Sprinkle the garlic powder, oregano, thyme, salt, and pepper over the top. This is where the magic starts to happen!
Covering Them in a Cheesy Blanket
It’s time for the best part! Cover the seasoned onions with the shredded mozzarella, cheddar, and finally, the grated Parmesan cheese. Don’t be shy with the cheese; it creates that irresistible golden crust.
Baking Until Golden and Bubbly
Bake the dish uncovered for about 35–40 minutes. You’ll know this incredible sweet onion recipe is ready when the onions are perfectly tender and the cheese is bubbly and beautifully browned. The aroma that fills the kitchen is pure comfort food southern heaven.
The Finishing Touch
Before you serve it, sprinkle a few fresh thyme sprigs over the top for a little touch of color and freshness. It’s ready to enjoy right away, warm from the oven.
Simple Swaps for a Lighter Version
- Reduce the Cheese: While the cheese is delicious, you can easily use half the amount for a lighter version that’s still packed with flavor.
- Use a Butter Substitute: For a lower-fat option, consider using a light butter alternative or even a drizzle of olive oil.
- Add More Veggies: Feel free to mix in some sliced bell peppers or mushrooms with the onions to add more nutrients and fiber to this delightful onion casserole.
My Favorite Ways to Serve These Onions
- Alongside a Roast: This is the ultimate side dish for a roast chicken, beef tenderloin, or a holiday ham. It’s how my dad always served it.
- With Grilled Meats: The cheesy, sweet onions are a perfect complement to a juicy grilled steak or simple pork chops.
- As a Hearty Topping: Spoon these baked onions over a burger or a grilled chicken sandwich for an instant flavor upgrade.
A Few of My Gentle Reminders
- Using the Wrong Onions: This recipe truly shines with a sweet onion like Vidalia or Walla Walla. Using a yellow or red onion will result in a sharper, less sweet flavor.
- Underbaking the Onions: Be sure to bake until the onions are completely tender. You can test this by piercing one with a fork; it should go through easily. If they’re still firm, they need more time.
- Not Covering the Dish if Cheese Browns Too Quickly: If you notice the cheese getting too dark before the onions are cooked through, simply cover the dish loosely with foil for the remainder of the baking time.
How to Keep Leftovers Fresh
Leftover Tennessee Onions can be stored in an airtight container in the refrigerator for up to 3 days. To reheat, simply place them in an oven-safe dish and bake at 350°F (175°C) until warmed through, or microwave for a minute or two.
From My Kitchen to Yours
Of all the onion recipes I’ve tried, this one holds the most warmth for me. It’s more than just a side dish; it’s a taste of home, of cozy Sunday afternoons spent in the kitchen. I hope that when you make it, it fills your home with the same warmth and brings as much joy to your table as it has to mine.
Your Questions, Answered
Which sweet onions work best?
Vidalia onions are the classic choice for their exceptional sweetness and mild flavor, which is perfect for this sweet onion recipe. However, Walla Walla or other sweet onion varieties will also work beautifully.
Can I make this dish in advance?
Yes, you can assemble the entire dish a day in advance. Just cover it tightly with plastic wrap and store it in the refrigerator. When you’re ready to bake, remove the plastic wrap and add about 5-10 extra minutes to the baking time.
Is it okay to swap the cheeses?
Absolutely! Feel free to experiment with your favorite melting cheeses. A mix of Gruyère, Monterey Jack, or even a little bit of smoked gouda would be delicious additions to these baked onions.
Print
Easy Tennessee Onions Recipe
- Total Time: 50 minutes
- Yield: 6 servings 1x
- Diet: Vegetarian
Description
This Easy Tennessee Onions Recipe transforms sweet onions into a cheesy, golden-brown side dish that’s pure comfort food. A simple casserole that’s crowd-pleasing, versatile, and perfect for Sunday dinners or holidays.
Ingredients
- 3–4 large sweet onions (like Vidalia)
- 4 tablespoons unsalted butter, melted
- 1 teaspoon garlic powder
- 1 teaspoon dried oregano
- 1 teaspoon dried thyme
- Salt and black pepper, to taste
- 1 cup shredded mozzarella cheese
- 1 cup shredded cheddar cheese
- 1/2 cup grated Parmesan cheese
- Fresh thyme sprigs, for garnish
Instructions
- Preheat oven to 375°F (190°C) and grease a 9×13-inch baking dish.
- Slice onions and arrange in the dish, layered or rolled into onion “roses.”
- Pour melted butter evenly over onions, then sprinkle with garlic powder, oregano, thyme, salt, and pepper.
- Top with mozzarella, cheddar, and Parmesan cheese.
- Bake uncovered for 35–40 minutes, until onions are tender and cheese is golden and bubbly.
- Garnish with fresh thyme sprigs before serving.
Notes
Use sweet onions like Vidalia or Walla Walla for best flavor. If cheese browns too quickly, cover loosely with foil. Leftovers can be stored in the fridge for up to 3 days and reheated in the oven or microwave.
- Prep Time: 10 minutes
- Cook Time: 40 minutes
- Category: Side Dish
- Method: Baked
- Cuisine: Southern American
Nutrition
- Serving Size: 1 serving
- Calories: 280
- Sugar: 5g
- Sodium: 420mg
- Fat: 20g
- Saturated Fat: 12g
- Unsaturated Fat: 7g
- Trans Fat: 0g
- Carbohydrates: 14g
- Fiber: 2g
- Protein: 9g
- Cholesterol: 55mg
Keywords: Tennessee onions, cheesy onions, baked onions, southern side dish, comfort food