Description
This French Onion Pasta Casserole combines the rich, deeply caramelized flavor of traditional French onion soup with creamy, cheesy pasta baked to bubbly perfection. Made with tender pasta coated in a luscious sauce of caramelized onions, thyme, garlic, and Gruyère cheese, this comforting casserole is topped with crispy fried onions for added texture and a golden crust. Ideal for a cozy family dinner, it merges the best elements of classic French and American comfort food in one hearty dish.
Ingredients
Scale
Pasta
- 12 oz pasta (such as penne or rigatoni)
Onion Sauce
- 2 tablespoons unsalted butter
- 2 tablespoons olive oil
- 3 large yellow onions, thinly sliced
- 1/2 teaspoon salt
- 1/4 teaspoon black pepper
- 1 tablespoon fresh thyme leaves (or 1 teaspoon dried thyme)
- 2 cloves garlic, minced
- 2 tablespoons all-purpose flour
- 1/2 cup dry white wine (optional)
- 2 cups beef broth (or vegetable broth for vegetarian)
- 1 cup heavy cream
- 1 teaspoon Worcestershire sauce (skip or use vegetarian version for vegetarian option)
Cheese and Toppings
- 2 cups shredded Gruyère cheese, divided
- 1/2 cup grated Parmesan cheese
- 1/2 cup crispy fried onions (for topping)
- Fresh parsley for garnish (optional)
Instructions
- Cook Pasta: Bring a large pot of salted water to a boil and cook the pasta until al dente, about 9-11 minutes depending on the pasta type. Drain and set aside.
- Caramelize Onions: In a large skillet or Dutch oven, heat the butter and olive oil over medium heat. Add the sliced onions, salt, and black pepper. Cook slowly, stirring often to prevent burning, for 25 to 30 minutes until the onions become deeply caramelized and golden brown.
- Add Herbs and Garlic: Stir in the fresh thyme and minced garlic into the caramelized onions and cook for an additional minute to release their fragrance.
- Make the Roux and Deglaze: Sprinkle the flour evenly over the onions and stir constantly to coat them and cook off the raw flour taste, about 1-2 minutes. Gradually pour in the dry white wine (if using), cooking for 2 minutes to deglaze the pan and reduce slightly.
- Add Liquids and Simmer: Pour in the beef broth, heavy cream, and Worcestershire sauce, stirring constantly. Let the mixture simmer and thicken for about 5 minutes until it reaches a creamy consistency.
- Add Cheese: Remove the skillet from heat and stir in 1 1/2 cups of Gruyère cheese and all of the Parmesan cheese until fully melted and smooth.
- Combine Pasta and Sauce: Mix the cooked pasta into the onion cheese sauce until everything is coated evenly.
- Assemble and Bake: Preheat the oven to 375°F (190°C). Transfer the pasta mixture to a greased 9×13-inch baking dish. Sprinkle the remaining 1/2 cup of Gruyère cheese evenly on top.
- Bake: Bake uncovered for 20 to 25 minutes until the casserole is bubbly and golden brown on top.
- Finish with Toppings: During the last 5 minutes of baking, sprinkle the crispy fried onions over the top to add a crunchy texture.
- Garnish and Serve: Remove from the oven and let rest for a few minutes. Garnish with fresh parsley if desired and serve warm.
Notes
- For a vegetarian version, substitute beef broth with vegetable broth and either omit Worcestershire sauce or use a vegetarian alternative.
- Swiss cheese can be used in place of Gruyère if unavailable.
- Dry white wine is optional but adds depth to the sauce; you may omit it if preferred.
- Leftovers keep well refrigerated for up to 3 days and can be reheated in the oven for best texture retention.
