Ingredients
1 1/2 tablespoons unsalted butter, cut into small pieces, plus more for baking dish
3 cups milk
4 tablespoons tomato paste
1 teaspoon coarse salt, plus more for water
1/2 teaspoon freshly ground pepper
1/4 teaspoon cayenne pepper, or to taste
3 cups grated white cheddar cheese
1 cup grated Swiss cheese
1 pound elbow macaroni
Sour cream, for serving
Preparation
Preheat oven to 375 degrees. Butter a 2 1/2-quart casserole dish; set aside.
Warm the milk and tomato paste in a medium saucepan over medium-low heat. Whisk in the salt, pepper, cayenne pepper, cheddar cheese, and 1/2 cup Swiss cheese; set the cheese sauce aside.
Cover a large pot of salted water, and bring to a boil. Cook until pasta is al dente, about 7 minutes. Drain well in a colander. Stir macaroni into reserved cheese sauce.
Pour mixture into prepared dish. Top with remaining 1/2 cup Swiss cheese, and dot with butter. Bake until golden brown and bubbling, about 45 minutes. Serve hot with sour cream, if desired.
