55min| 12 servings | 455 cal

"This is really good, even for days later, for leftovers."

INGREDIENTS

1 16-oz package elbow macaroni
1 tsp salt, divided
4 cups butter, softened and divided
1 cup sour cream
1 tbsp cream cheese, softened
1 8-oz package sharp cheddar cheese, shredded
1 8-oz package mild cheddar cheese, shredded
1 egg yolk
2 tbsp all-purpose flour
1/2 tbsp cayenne pepper
1 cup milk

DIRECTIONS

Prep: 30min | Cook: 25min | Ready in: 55min

Step 1

Preheat oven to 375°F (190°C). Line a 9- x 13-inch baking dish with parchment paper.

Step 2

Bring a large pot of water to a boil. Cook elbow macaroni in the boiling water, stirring occasionally until almost cooked through and firm to the bite, about 7 minutes. Drain and transfer to a large bowl. Sprinkle ½ tsp salt over macaroni, and stir in ½ cup butter. 

Step 3

Combine ¼ cup butter, sour cream, cream cheese, sharp cheddar cheese and egg yolk together in a bowl; mix together. Stir in flour, ½ tsp salt, cayenne pepper and milk.

Step 4

Spread ¼ cup sour cream sauce over bottom of prepared baking dish. Stir remaining sour cream sauce into the macaroni. Pour macaroni into baking dish atop sauce layer; sprinkle mild cheddar cheese over the casserole.

Step 5

Bake until heated through and cheese is melted, about 15 minutes.