Classic Baked Macaroni and Cheese Casserole

Name: Classic Baked Macaroni and Cheese Casserole
Prep time: 10 min
Cook time: 70 min
Total time: 80 min
Yield: 8
Ingredients: Kosher salt; 1 pound (450g) elbow macaroni; 7 tablespoons (105g) unsalted butter, divided; 2 tablespoons (16g) all-purpose flour; 2 cups (475ml) milk; 12 ounces (340g) grated sharp cheddar cheese (see note); 1 teaspoon (5ml) hot sauce, such as Frank's RedHot; 1/2 teaspoon (2g) mustard powder; 1/4 teaspoon (1g) garlic powder; 1/4 pound (115g) grated Gruyère cheese (see note); 1 cup panko bread crumbs (2 ounces; 55g)