Trinidadian Macaroni Pie

Name: Trinidadian Macaroni Pie
Ingredients: 1 tablespoon plus 1 teaspoon salt , divided; 1 pound bucatini or elbow macaroni; 2 tablespoons unsalted butter; 2 ( 12 - ounce ) cans evaporated milk; 3 tablespoons ketchup; 2 tablespoons yellow mustard; 2 teaspoons neutral cooking oil; 3 pimento peppers , minced (see recipe note); 1/4 yellow onion , grated; 3 large garlic cloves , grated on a microplane or pressed in a garlic press; 1 teaspoon black pepper; 1 teaspoon paprika; 1/2 teaspoon cayenne pepper , optional; 2 eggs , beaten; 8 ounces shredded extra sharp white cheddar cheese, divided; 16 ounces shredded extra sharp yellow cheddar cheese, divided