Ingredients

• 2 tablespoons butter (for sauerkraut filling)
• 1/3 cup chopped onion (for sauerkraut filling)
• 1 1/2 cups sauerkraut, drained
• 3 tablespoons butter (for potato filling)
• 1/2 cup chopped onion (for potato filling)
• 2 cups mashed potatoes
• 3 eggs
• 1 cup sour cream
• 3 cups all-purpose flour
• 1/4 teaspoon salt
• 1 tablespoon baking powder
• to taste salt and pepper

Equipment

• Large skillet
• Large pot
• Mixing bowls
• Rolling pin
• 3 inch biscuit cutter or glass
• Slotted spoon

Instructions

1. Make the sauerkraut filling: melt 2 tablespoons butter in a skillet over medium heat, add the 1/3 cup onion, and cook until soft and translucent, about 5 minutes, so it turns sweet instead of sharp.
2. Stir in the drained sauerkraut and cook 5 more minutes to warm through and blend the flavors. Season with salt and pepper, then scrape onto a plate to cool completely.
3. Make the potato filling: melt 3 tablespoons butter in a skillet over medium heat, add the 1/2 cup onion, and cook until translucent, about 5 minutes. Stir the buttery onions into the mashed potatoes and season with salt and a pinch of white pepper. Let cool.
4. Make the dough: in a large bowl, whisk the eggs and sour cream until smooth. Sift the flour, 1/4 teaspoon salt, and baking powder together, then stir into the wet mixture until a shaggy dough forms.
5. Turn the dough out onto a lightly floured surface and knead until firm, smooth, and no longer sticky, about 5 minutes. Divide in half.
6. Roll one half out to about 1/8 inch thick and cut into 3 inch rounds with a biscuit cutter or glass. Gather and reroll scraps as needed.
7. Spoon a small mound of potato filling into the center of each round. Moisten the edges with water, fold into a half moon, and press the edges firmly with a fork to seal so they do not open while boiling.
8. Repeat with the second half of dough and the sauerkraut filling.
9. Bring a large pot of lightly salted water to a boil. Drop in the pierogi in batches and cook 3 to 5 minutes, until they float to the top. Lift out with a slotted spoon and serve warm.