Ultimate Lobster Mac and Cheese

Name: Ultimate Lobster Mac and Cheese
Ingredients: kosher salt; 1 lb elbow macaroni or 1 lb your favorite macaroni; 1 quart whole milk; 1⁄2 cup unsalted butter; 1⁄2 cup all-purpose flour; 4 cups extra-sharp white cheddar cheese, grated; 8 ounces brie cheese; 1⁄2 teaspoon fresh ground black pepper; 1⁄2 teaspoon freshly grated nutmeg; 1 1⁄2 lbs cooked lobster meat