- Salt and pepper
- 1 pound whole wheat macaroni or penne pasta
- 3 tablespoons butter
- 2 large onions, peeled, quartered and thinly sliced
- 1 bay leaf
- 1 teaspoon ground thyme (about 1/3 palmful)
- 2 tablespoons flour
- 1 1/2 cups whole milk
- 1/2 cup beef stock
- 2 1/2 cups grated Gruyère or Swiss cheese, divided
- 2 tablespoons dijon mustard
- 1/4 cup chives, finely chopped
Bring a large pot of water to a boil, salt it, add the pasta and cook according to the package directions to al dente; drain.
While the pasta is working, heat a large, deep skillet over medium-high heat. Add the butter to melt, then add the onions, bay leaf and thyme; season with salt and pepper. Cook, stirring occasionally, until the onions are light caramel in color, 15-20 minutes.
Pre-heat the broiler. Discard the bay leaf. Stir the flour into the onion mixture. Stir in the milk and beef stock and bring to a boil. Cook, stirring, until thickened, about 2 minutes. Remove from the heat and stir in 1 1/2 cups cheese until melted, then stir in the mustard.
Add the pasta to the sauce and toss. Spoon into a 9-inch x 13-inch casserole dish, top with the remaining 1 cup cheese and broil until brown, 2-4 minutes. Top with the chives and serve immediately.