Ingredients
Equipment
Method
Prepare and bake the casserole
- Preheat the oven to 350°F.
- Coat a 9x13-inch baking dish with nonstick cooking spray.
- Bring the water to a boil in a large pot, add 1 tablespoon of the salt, and cook the noodles 1 minute less than the shortest time on the package directions.
- Drain the noodles.
- Melt the butter in a 12-inch skillet over medium-low heat.
- Add the onions and cook for 25 to 30 minutes, stirring often, until soft and golden brown.
- Add the ground beef, the remaining 1 teaspoon salt, and the pepper; cook, breaking up the beef, until browned and it reaches 160°F.
- Stir in the flour and cook for 1 minute.
- Gradually stir in the broth, Worcestershire sauce, and thyme.
- Simmer for 3 to 5 minutes, stirring, until the sauce thickens slightly.
- Remove the skillet from the heat and stir in the sour cream and 1 1/2 cups of the Gruyere.
- Fold in the drained noodles.
- Spread the mixture in the prepared dish and sprinkle with the remaining 1/2 cup Gruyere.
- Bake for 20 to 25 minutes, until hot and bubbling.
Add the topping
- Scatter the French-fried onions over the casserole.
- Bake for 5 minutes, until crisp and golden.
- Let the casserole rest for 10 minutes before serving.
Notes
For the deepest onion flavor, cook the onions slowly until soft and golden brown. Refrigerate leftovers for 3 to 4 days; freezer-friendly for up to 3 months. For a gluten-free variation, use certified gluten-free noodles, flour, and French-fried onions.
