perogies recipe

Ingredients: For the Dough: 2 cups all-purpose flour 1/2 teaspoon salt 1 large egg 1/2 cup sour cream 1/4 cup unsalted butter, softened For the Potato and Cheese Filling: 2 cups mashed potatoes (about 4 medium potatoes) 1 cup shredded cheddar cheese 1 small onion, finely chopped 2 tablespoons butter