Lobster Mac and Cheese

Name: Lobster Mac and Cheese
Ingredients: 2 tablespoons vegetable oil; Kosher salt; 1 pound cavatappi or elbow macaroni; 1 quart whole milk; 8 tablespoons (1 stick) unsalted butter, divided; 1/2 cup all-purpose flour; 4 cups grated Gruyere cheese (12 ounces); 2 cups grated extra-sharp Cheddar (8 ounces); 1/2 teaspoon freshly ground black pepper; 1/2 teaspoon ground nutmeg; 1 1/2 pounds cooked lobster meat, 1/2-inch-diced; 1 1/2 cups fresh white bread crumbs (5 slices, crusts removed)