Use a mix of cheeses, such as sharp cheddar and Gruyère
Cook pasta until just al dente
Salt the pasta water well
Make a smooth roux with butter and flour
Whisk in milk gradually to avoid lumps
Season the sauce with salt, pepper, and a little mustard powder
Add cheese off the heat to prevent graininess
Reserve some pasta water for adjusting consistency
Combine pasta and sauce thoroughly
Add a crispy topping with breadcrumbs and butter
Bake until bubbly and golden
Let it rest briefly before serving