- 4 tablespoons butter, divided
- 2 large onions, very thinly sliced
- 1 teaspoon ground thyme
- 1 bay leaf
- Salt and pepper
- 1 pound penne rigate or whole wheat penne rigate pasta
- 2 tablespoons flour
- 1 cup chicken stock
- 1 cup whole milk
- Freshly grated nutmeg
- 3/4 pound Gruyère cheese, shredded
In a skillet, melt 2 tablespoons butter over medium-high heat. Stir in the onions, thyme and bay leaf for 5 minutes; season with salt and pepper. Lower the heat and cook until the onions are browned, 10-15 minutes. Transfer to a plate and discard the bay leaf. Reserve the skillet.
Meanwhile, bring a large pot of water to a boil, salt it, add the pasta and cook until al dente. Drain and return to the pot.
In the reserved skillet, melt the remaining 2 tablespoons butter over medium heat. Whisk in the flour for 1 minute, then whisk in the chicken stock and milk and bring to a boil; season with salt, pepper and nutmeg. Lower the heat and cook until thickened, about 5 minutes. Stir in the cheese until melted.
Combine the onions and sauce with the pasta and toss well.