If you’re on the hunt for comfort food with a sophisticated twist, look no further: this French Onion Pasta Casserole Recipe brings together the caramelized depth of classic French onion soup with the nostalgia of a creamy baked pasta. Imagine layers of tender noodles coated in sweet, golden onions, bathed in a savory cream sauce, and blanketed under a bubbling, cheesy crust. Whether it’s a cozy family dinner or a friend-filled weekend gathering, this dish promises to steal the show—and have everyone asking for seconds. With flavor this layered, you’ll never look at pasta bake the same way again!

French Onion Pasta Casserole Recipe - Recipe Image

Ingredients You’ll Need

The ingredients here may look familiar, but each one plays a crucial role in building the irresistible flavors and textures that define this French Onion Pasta Casserole Recipe. Gather everything below for a guaranteed crowd-pleaser—don’t skip a thing, because every component truly counts!

Pasta (12 ounces, such as penne or rotini): Hearty shapes like penne or rotini soak up the oniony sauce beautifully, making every bite satisfying.
Unsalted butter (2 tablespoons): Essential for coaxing out the richest, sweetest flavors from the onions and creating silky caramelization.
Olive oil (2 tablespoons): Blends with the butter to prevent burning and adds a subtle fruitiness to the base.
Yellow onions (2 large, thinly sliced): The stars of the dish—cooked low and slow, they turn deeply golden and sweet, infusing every layer with flavor.
Salt (1/2 teaspoon): Balances the intense sweetness of the onions.
Black pepper (1/2 teaspoon): Adds gentle warmth to each forkful.
Sugar (1/4 teaspoon): Just a pinch accelerates and deepens that glorious onion caramelization.
Garlic (2 cloves, minced): One quick sauté at the end brightens the whole dish with aromatic complexity.
All-purpose flour (1 tablespoon): Lightly thickens the sauce so it clings perfectly to your pasta.
Beef broth (1 cup): Provides a savory, meaty backbone reminiscent of traditional French onion soup.
Heavy cream or half-and-half (1/2 cup): Lends silky richness, tying together all those deep flavors.
Fresh thyme leaves (1 teaspoon) or dried (1/2 teaspoon): Gives that subtle herbal lift that’s unmistakably French-inspired.
Gruyère cheese (1 cup, shredded; or Swiss): Nutty, melty Gruyère is the signature cheese for authentic flavor and gooey texture.
Mozzarella cheese (1/2 cup, shredded): Adds melt and stretch without overpowering the other flavors.
Parmesan cheese (1/4 cup, grated): Offers a golden, sharp finishing touch on top.
Chopped parsley (for garnish, optional): A sprinkle of freshness just before serving makes every plate pop.

How to Make French Onion Pasta Casserole Recipe

Step 1: Cook the Pasta

Start by preheating your oven to 375°F and generously greasing a 9×13-inch baking dish. Meanwhile, boil your favorite pasta shapes in well-salted water until they’re just al dente—firm to the bite, but cooked through. Drain them and set aside; they’ll finish cooking in the oven while soaking up all those savory juices.

Step 2: Caramelize the Onions

In your largest skillet, melt the butter and olive oil over medium-low heat. Pile in those mountains of thinly sliced onions, seasoning immediately with salt, pepper, and a pinch of sugar. Stir often and let them cook gently for 25 to 30 minutes—patience is key! You’ll watch the onions transform from sharp and raw to soft, deeply golden, and irresistibly sweet-smelling. Just before they’re done, add the minced garlic, stirring until aromatic.

Step 3: Make the Sauce

Once the onions are caramelized, sprinkle flour evenly over the mixture, stirring well so no lumps remain. Little by little, add the beef broth, scraping up every bit of brown flavor from the pan. Let the sauce bubble and thicken slightly, then stir in your cream or half-and-half, along with the fresh thyme. This is the luscious, craveable heart of the French Onion Pasta Casserole Recipe.

Step 4: Combine Pasta and Cheese

Add your cooked, drained pasta to the skillet. Toss generously so every piece is coated, then stir in the shredded Gruyère and mozzarella cheese. Watch them begin to melt and turn creamy—now you’re almost ready for the oven!

Step 5: Assemble and Bake

Transfer the cheesy, oniony pasta mixture into your prepared baking dish. Sprinkle the grated Parmesan over the top for flavor and crunch. Place the dish (uncovered) in your preheated oven and bake for 15 to 20 minutes, watching as the top turns bubbly and a bit golden. For the best results, let the casserole rest for 5 minutes before serving, allowing the flavors to settle. Top with a scattering of chopped parsley for a burst of color, if desired.

How to Serve French Onion Pasta Casserole Recipe

Garnishes

Freshly chopped parsley is a classic finish, offering color and a light, fresh counterpoint to all the rich cheese and onions. For an extra flourish, try a shower of more Parmesan or even a crack of black pepper served tableside—it lends both flavor and elegance. If you’re feeling adventurous, minced chives make a lovely alternative!

Side Dishes

This French Onion Pasta Casserole Recipe is a star all by itself, but it shines even brighter next to a crisp green salad tossed in tangy vinaigrette, or simple roasted vegetables to round out the meal. A pillowy loaf of crusty bread on the side is perfect for scooping up any sauce left on your plate.

Creative Ways to Present

For a show-stopping dinner, divide the casserole into individual baking dishes or oven-safe ramekins before baking. Or, serve it family-style right from the oven in your prettiest casserole dish, letting everyone help themselves. A sprinkle of extra cheese or herbs over each serving just before plating can turn a normal dinner into something truly memorable.

Make Ahead and Storage

Storing Leftovers

Leftovers will keep beautifully in an airtight container in the refrigerator for up to four days—making weeknight lunches something to seriously look forward to. Just let the casserole cool to room temperature before storing to prevent condensation and sogginess.

Freezing

You can definitely freeze portions of this French Onion Pasta Casserole Recipe! Simply let it cool completely, then wrap tightly in plastic wrap and foil. It will keep in the freezer for up to two months. Thaw overnight in the fridge for best texture.

Reheating

Rewarm individual portions in the microwave, or bring the whole (thawed) casserole back to life in a 350°F oven for about 20 minutes, covered loosely with foil to prevent over-browning. A quick sprinkle of extra cheese on top before reheating adds some fresh gooeyness!

FAQs

Can I use a different type Main Course

Absolutely! While penne or rotini are classic choices for the French Onion Pasta Casserole Recipe, any sturdy short pasta will work—like rigatoni, fusilli, or even shells. Just be sure not to overcook them initially, as they’ll soften further in the oven.

How do I make this vegetarian?

It’s easy—simply swap the beef broth for vegetable broth. Make sure whichever broth you use is full-flavored, as it provides much of the rich foundation in this casserole.

Can I add protein or extra veggies?

Yes! Shredded cooked chicken or sautéed mushrooms fit perfectly with the other flavors in this recipe. Stir them in with the pasta before baking for a heartier version, and adjust seasonings as needed.

What’s the best cheese substitute for Gruyère?

If Gruyère is hard to find or a bit pricey, Swiss cheese is a great substitute. Fontina or even cheddar can work in a pinch, but Gruyère is the classic choice for authentic flavor.

Can I make this ahead of time?

You sure can! Assemble the French Onion Pasta Casserole Recipe (but don’t bake), cover tightly, and refrigerate for up to 24 hours. Bake just before serving, adding a few extra minutes if baking straight from the fridge.

Final Thoughts

This French Onion Pasta Casserole Recipe is the kind of dish that feels both nostalgic and elevated—a real celebration of comfort and flavor. Put it on your table this week and watch it disappear! If you’re craving cozy, cheesy, and full-on depth, you simply have to give this a try. Happy cooking!

French Onion Pasta Casserole Recipe

5 Stars 4 Stars 3 Stars 2 Stars 1 Star

4.9 from 21 reviews

Author: Emma
Total Time: 1 hour
Yield: 6 servings 1x
Diet: Non-Vegetarian

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Description

Indulge in the rich and comforting flavors of this French Onion Pasta Casserole. Caramelized onions, creamy sauce, and gooey cheese come together with pasta for a satisfying meal that’s perfect for a cozy night in.

Ingredients

Scale

Pasta:

12 ounces pasta (such as penne or rotini)

Caramelized Onions:

2 tablespoons unsalted butter
2 tablespoons olive oil
2 large yellow onions (thinly sliced)
1/2 teaspoon salt
1/2 teaspoon black pepper
1/4 teaspoon sugar
2 cloves garlic (minced)

Sauce:

1 tablespoon all-purpose flour
1 cup beef broth
1/2 cup heavy cream or half-and-half
1 teaspoon fresh thyme leaves (or 1/2 tsp dried)

Cheese:

1 cup shredded Gruyère cheese (or Swiss)
1/2 cup shredded mozzarella
1/4 cup grated Parmesan

Garnish:

chopped parsley for garnish (optional)

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Instructions

Preheat oven to 375°F. Grease a 9×13-inch baking dish.
Cook pasta in salted water until al dente, then drain and set aside.
Caramelize onions: In a skillet, cook onions with salt, pepper, and sugar until golden. Add garlic.
Make sauce: Sprinkle flour over onions, then add beef broth, cream, and thyme. Simmer.
Combine: Mix cooked pasta with sauce and cheeses. Transfer to baking dish and top with Parmesan.
Bake: Uncovered for 15–20 minutes until golden. Let rest before serving. Garnish with parsley.