Creamy Macaroni and Cheese

2 cups uncooked elbow macaroni
4 tablespoons butter, cut into pieces
2 1/2 cups grated sharp Cheddar cheese
3 eggs, beaten
1/2 cup sour cream
1 (10 3/4 oz) can condensed Cheddar cheese soup
1/2 teaspoon salt
1 cup whole milk
1/2 teaspoon dry mustard
1/2 teaspoon black pepper

Boil the macaroni in a 2 quart saucepan in plenty of water until tender, about 7 minutes. Drain. In a medium saucepan, mix butter and cheese. Stir until the cheese melts. In a slow cooker, combine cheese/butter mixture and add the eggs, sour cream, soup, salt, milk, mustard and pepper and stir well. Then add drained macaroni and stir again. Set the slow cooker on low setting and cook for 3 hours, stirring occasionally.