Pre-heat oven to 375 degrees F

Boil pasta for 6 minutes (or 3 minutes below package instructions for al dente). Drain pasta. The pasta should be slightly undercooked

While the pasta boils, heat milk in a saucepan until warmed but not boiling

In a separate pot (large enough to mix that macaroni and cheese) melt 6 tablespoons of butter. Add the flour and whisk over low heat for 2 minutes. After 2 minutes, slowly stream in the hot milk (whisking vigorously) and cook for 2 more minutes until smooth

Turn off the heat and add gruyere, cheddar, salt, pepper, and nutmeg. Add the cooked pasta and stir until combined. Place in a 9x13” baking dish

Melt the remaining 2 tablespoons of butter and combine with bread crumbs. Sprinkle mixture over the top and bake for 30 minutes until golden on top and bubbling