Prep time 15 minutes
Cook time 20 minutes
Yield: Serves or Makes 4
Bring a large pot of salted water to a boil then add the pasta. Cook the pasta for 2 minutes less than the time directed for al dente on the package. It will cook more in the cheese sauce and we do not want overcooked noodles. When pasta is done boiling, reserve some of the pasta water before draining into a colander and set aside.
Roughly dice mozzarella into small pieces and shred cheddar cheese. The mozzarella helps add gooeyness to the pasta since it has a high moisture content, and the cheddar brings the flavor; I recommend preparing a bit more cheese of each amount in case you need to adjust here and there at the end.
Turn the burner to low heat and melt the butter. Once butter is melted, whisk the flour in bit by bit until it forms a thick paste (this is the roux). Slowly whisk in the milk. Continuously stir for 5-10 minutes, until it transforms from thin and liquidy to a thickened sauce (this is the bechamel).
Stir in cheese slowly, adding bit by bit. I alternate between adding some mozzarella and some cheddar at a time. Adding cheese gradually helps it to melt evenly into the sauce. Make adjustments as necessary – if the sauce seems too stringy, add more cheddar to offset the mozzarella; if the sauce seems too thin, add more mozzarella to make it nice and gooey.
Stir in salt, pepper, and mustard. Add pasta to the pot and stir until it is well incorporated into the sauce.
Stir in a small amount of pasta water to pull the sauce together until you get to a desired consistency (you shouldn’t need a lot, just a bit to loosen up the cheese mixture and pull everything together).
Add crushed red pepper if you like. Add any additional salt needed to boost your flavor and you’re good to go.