Creamy stovetop shells in a velvety sharp cheddar and Gruyere mornay sauce.
8 steps, about 30 minutes start to finish.
Cook pasta in well-salted boiling water until al dente. Drain, reserving 1/2 cup pasta water.
Melt butter in a large saucepan over medium heat. Whisk in flour and cook for 2 minutes.
Gradually whisk in warm milk, then cream. Cook, stirring constantly, until thickened, about 5 minutes.
Remove from heat and stir in mustard, garlic powder, and cayenne.
Add cheeses a handful at a time, stirring until melted and smooth.
Season with salt and white pepper.
Toss pasta with sauce, adding reserved pasta water if needed to loosen.
Serve immediately.
“Add the cheese off the heat, a handful at a time, letting each melt in before the next. Dump it all in at once over high heat and the sauce turns grainy instead of silky.”