Step 1

Preheat oven to 400.

Step 2

Bring a large pot of water to a boil. Add a small handful of salt and add pasta. Cook pasta according to package directions, to the lowest cook time suggested. (For instance, if it says 9-11 minutes, cook for only 9 minutes.) Remove and drain pasta and set aside.

Step 3

Meanwhile, in a large pot, melt 3 tablespoons of butter over medium heat. Add flour and cook for one to two minutes, whisking constantly.

Step 4

Slowly add in 2 cups milk, whisking constantly, until the mixture is smooth.

Step 5

Add the Gruyere cheese and stir until melted. Add salt and pepper and stir again. Remove from heat and add cooked pasta. Stir well to coat all of the pasta and get everything combined.

Step 6

Transfer the pasta and sauce to a greased 2-quart casserole dish. Top with the shredded cheddar cheese.

Step 7

In a small bowl, combine breadcrumbs with the 3 tablespoons of melted butter and stir to combine.

Step 8

Sprinkle breadcrumb mixture on top of the casserole. Bake at 400 for 20 minutes, until hot and bubbly. Let sit for 4-5 minutes before serving.