INGREDIENTS
•
4 tablespoons unsalted butter, divided
•
3/4 cup panko (Japanese breadcrumbs)
•
1 ounce Parmesan, finely grated (about 1/4 cup)
•
2 teaspoons fresh thyme leaves
•
1 teaspoon kosher salt, divided, plus more
•
8 ounces cavatappi or other short curly pasta
•
2 1/2 cups whole milk
•
1/2 small onion, grated
•
1 garlic clove, finely grated
•
2 tablespoons all-purpose flour
•
4 ounces Fontina cheese, grated (about 1 cup)
•
4 ounces Gruyère, grated (about 1 cup)
•
4 ounces sharp white cheddar, grated (about 1 cup)
•
1/2 teaspoon English mustard powder (such as Colman’s)
•
Pinch of cayenne pepper