Preparation Steps

• Place the potatoes in a large pot and cover with water. Bring to a boil and simmer until fork tender, about 15 minutes. Drain and mash. Chill the mashed potatoes.
• In a skillet, heat olive oil and sauté the chopped onion until tender. Cool slightly and add to chilled mashed potatoes. Rinse sauerkraut very well, drain thoroughly, then add to potato mixture with cheese. Mix to combine and refrigerate until use.
• In a large bowl, combine flour and salt. Make a well, crack in the egg, and stir. Gradually add hot water, mixing until dough is sticky and cohesive. Add more flour if too sticky. Chill dough for at least one hour.
• Bring a large pot of water to boil. Lightly flour a surface and knead dough briefly, adding flour as needed.
• Divide dough into four sections. Roll out one section very thin (about 1/8 inch). Cut circles and place 1 tablespoon of filling on one side. Fold over and pinch edges to seal. Arrange pierogies in a single layer on a plate without stacking.
• Boil pierogies in batches, gently stirring to prevent sticking. When they float, remove with a slotted spoon. Place on buttered plates, drizzle with melted butter, and let cool slightly before frying.
• Heat butter in a skillet over medium heat. Fry pierogies in a single layer for 2-3 minutes per side until edges are golden and crisp. Remove and keep warm until serving.