Baked Macaroni and Cheese

INGREDIENTS

• 1 teaspoon Worcestershire sauce (optional)
• 1 pound elbow macaroni
• Kosher salt
• 1/4 cup all-purpose flour
• 8 ounces havarti cheese, grated (about 2 cups)
• 1 pound sharp yellow cheddar cheese, grated (about 4 cups)
• 1 sleeve butter crackers (such as Ritz), crushed (about 35 crackers)
• 2 teaspoons mustard powder
• 12 ounces white American cheese, grated (about 3 cups)
• 1 teaspoon hot sauce
• 1 quart whole milk
• 1/4 teaspoon cayenne pepper
• 2 tablespoons grated parmesan cheese (optional)
• 1 stick unsalted butter, plus melted butter for brushing