Name: Tennessee Onions: Old-Fashioned Onion Casserole with Cheddar and Gouda Recipe
Prep time: 15 min
Cook time: 1 h 10 min
Total time: 1 h 25 min
Cuisine: American Southern
Ingredients: Cooking spray; 2 1/2 lb. sweet onions (about 3 large onions), sliced crosswise into 1/4-inch-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-inch-thick pieces; 4 oz. mild Cheddar cheese, shredded (about 1 cup); 4 oz. smoked Gouda cheese, shredded (about 1 cup)

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If you're craving a side dish that will steal the spotlight at any meal, you simply must try the Tennessee Onions: Old-Fashioned Onion Casserole with Cheddar and Gouda Recipe. This comforting casserole transforms humble sweet onions into a rich, cheesy delight accented by a fragrant blend of herbs and spices. The mix of mild Cheddar and smoked Gouda creates a luscious, melty crust that perfectly complements the tender, savory onions beneath. It’s a timeless recipe that brings warmth to the table and makes the familiar feel extraordinary.

Ingredients You'll Need

A wooden table holds a variety of small glass bowls filled with different ingredients arranged neatly. On the left side, there are two small glass bowls filled with shredded white and yellow cheese. Above these are smaller glass bowls containing dried herbs, seasonings, and small cubes of pale yellow butter. On the right side, a large white bowl is filled with thick, evenly sliced white onion rings stacked in a layered manner. The setup is clear and organized, showing ingredients ready for preparation, photo taken with an iphone --ar 4:5 --v 7

Gathering a handful of straightforward ingredients is all it takes to bring this luscious casserole to life. Each one plays a key role, from the sweet, tender onions that form the base to the blend of herbs that lift the flavors with an aromatic touch. The cheeses add creamy, gooey goodness while the butter ensures everything bakes up beautifully golden and bubbling.

Cooking spray: Prevents sticking and helps the casserole crisp up nicely.
2 ½ lb. sweet onions: About 3 large onions sliced into ¼-inch rings; the star ingredient offering natural sweetness and tenderness.
1 tsp. dried thyme: Adds a subtle earthy tone that complements the onions perfectly.
1 tsp. dried parsley flakes: For a fresh, slightly peppery flavor that brightens the casserole.
1 tsp. garlic salt: Deepens the savoriness with a garlicky punch without overpowering.
½ tsp. dried oregano: Introduces a warm, herbaceous note to balance the cheese.
½ tsp. dry mustard: Gives a mild tanginess that enhances the overall flavor complexity.
¼ tsp. cayenne pepper: A gentle hint of heat that wakes up your taste buds.
¼ cup salted butter: Cut into small pieces to melt evenly over the onions, adding richness.
4 oz. mild Cheddar cheese: Shredded to create melty, creamy pockets of flavor.
4 oz. smoked Gouda cheese: Shredded for a smoky, velvety contrast that makes each bite unforgettable.

How to Make Tennessee Onions: Old-Fashioned Onion Casserole with Cheddar and Gouda Recipe

Step 1: Prepare the Onions

Start by peeling the sweet onions and slicing them crosswise into quarter-inch thick slices. Gently separate these slices into individual rings to help them cook evenly and absorb all those lovely seasonings.

Step 2: Season the Onion Rings

In a large bowl, combine the dried thyme, parsley flakes, garlic salt, oregano, dry mustard, and cayenne pepper. Toss the onion rings thoroughly so every ring gets a coating of this flavorful herb and spice mix that will elevate the dish beyond ordinary.

Step 3: Arrange Onions and Add Butter

Spray your casserole dish lightly with cooking spray to keep things from sticking, then spread the seasoned onions evenly. Scatter the quarter-inch pieces of salted butter evenly across the top. This step is crucial for achieving a rich, golden crust as the casserole bakes.

Step 4: Add Toppings and Bake

Sprinkle the shredded mild Cheddar and smoked Gouda evenly over the buttered onions. Cover the dish tightly with aluminum foil to trap moisture and help the onions soften thoroughly. Bake in a preheated oven at 350°F for about 40 minutes, allowing the casserole’s sides to bubble beautifully.

Step 5: Finish Baking

Remove the foil and continue baking at 350°F for an additional 30 minutes. This final stage creates a stunningly golden, slightly crisp cheese topping that adds texture and deep flavor to your classic casserole.

How to Serve Tennessee Onions: Old-Fashioned Onion Casserole with Cheddar and Gouda Recipe

A blue rectangular baking dish filled with a creamy baked dish topped with many layers of cooked onion rings. The onions are golden brown on the edges, with some parts looking melted and slightly crispy. The creamy sauce beneath the onions is light yellow with herbs sprinkled on top. The dish sits on a wooden surface. photo taken with an iphone --ar 4:5 --v 7

Garnishes

A scattering of fresh parsley or chives on top adds a pop of color and a mild herbal freshness that contrasts wonderfully with the smoky cheese. For a little extra zest, a light dusting of smoked paprika can highlight the Gouda's natural smoky notes.

Side Dishes

This casserole pairs exceptionally well with roasted meats like turkey or pork, as well as with rustic breads and green vegetable sides. Think crisp green beans or a simple mixed leaf salad that refreshes the palate between creamy, cheesy bites.

Creative Ways to Present

For a charming twist, serve individual portions in small ramekins or cast-iron skillets to retain heat and add a rustic touch. You can also build this casserole as a layered side for holiday spreads to make it visually stunning and inviting to guests.

Make Ahead and Storage

Storing Leftovers

Once cooled, store any leftover Tennessee Onions: Old-Fashioned Onion Casserole with Cheddar and Gouda Recipe in an airtight container in the fridge. It will keep well for up to four days, making it perfect for quick reheats as a delicious side.

Freezing

You can freeze this casserole for longer storage. Transfer to a freezer-safe container after baking but before the final melt and browning step. Freeze for up to three months, then bake from frozen by adding extra baking time.

Reheating

Reheat the casserole in a 350°F oven until warmed through and the cheese is once again melty. If reheating from frozen, thaw overnight in the fridge for best results, then proceed to heat and crisp the top gently under a broiler if desired.

FAQs

Can I use other types of onions instead of sweet onions?

Sweet onions provide a mild, naturally sugary flavor that balances the savory cheese perfectly. You could use yellow onions but be aware the dish may turn out sharper and less sweet, which could change its classic character.

Is it possible to substitute the cheeses?

Yes! While Cheddar and smoked Gouda are preferred for their blend of sharpness and smokiness, you can experiment with other mild cheeses and smoked varieties to suit your taste or what you have on hand.

Can I make this casserole vegan or dairy-free?

To veganize this beloved dish, substitute the butter with plant-based margarine and pick dairy-free cheese alternatives that melt well. The herbs and onions remain the stars either way!

What side dishes complement Tennessee Onions best?

Green vegetables like roasted asparagus or sautéed spinach work wonderfully, as do roasted or mashed potatoes. A fresh salad can also balance out the richness of the casserole.

How long does it take to prepare and bake?

Preparation is fairly quick—about 15 minutes to slice and season onions—plus about 1 hour and 10 minutes in the oven, so it’s best to plan accordingly for a leisurely cooking experience.

Final Thoughts

Tennessee Onions: Old-Fashioned Onion Casserole with Cheddar and Gouda Recipe is a delightful side that feels like a warm hug in every bite. It’s perfect for gatherings, family meals, or anytime you want a comforting dish that’s easy to make yet so impressive. Trust me, once you try it, it will become your go-to casserole to brighten the table and satisfy every craving for cheesy, savory goodness.

Tennessee Onions: Old-Fashioned Onion Casserole with Cheddar and Gouda Recipe

Ingredients You'll Need