Preparation Steps

• In a mixing bowl, combine the mashed potatoes, shredded cheddar, and salt. Mix well.
• In another bowl, mix the flour, egg, and a pinch of salt to form a dough.
• Roll out the dough on a floured surface to about 1/8 inch thickness.
• Cut the dough into circles using a cookie cutter or glass.
• Place a spoonful of the potato mixture in the center of each circle.
• Fold the dough over to create a half-moon shape; seal edges tightly.
• In a large pot, bring salted water to a boil. Cook the pierogi in batches until they float, about 5 minutes.
• In a skillet, melt the butter over medium heat and sauté the chopped onions until golden.
• Add the cooked pierogi to the skillet and fry until they're golden brown on each side.