Instructions
To prepare the sauerkraut filling: Melt 2 tablespoons of butter in a skillet over medium heat. Add 1/3 cup of chopped onion. Cook for 5 minutes, stirring until the onion is translucent and soft. Add 1.5 cups of drained sauerkraut. Cook for an additional 5 minutes, stirring occasionally. Season to taste with salt and pepper. Remove the sauerkraut filling to a plate and let it cool completely. To prepare the mashed potato filling: Melt 3 tablespoons of butter in a clean skillet over medium heat. Add 1/2 cup of chopped onion. Cook for 5 minutes, stirring until the onion is translucent and soft. Stir the cooked onion and butter into 2 cups of mashed potatoes. Season to taste with salt and white pepper. To make the dough: In a medium bowl, beat 3 eggs and 1 pot of sour cream together until smooth. In a separate bowl, sift together 3 cups of flour, 1/4 teaspoon of salt, and 1 tablespoon of baking powder. Gradually add the sifted dry ingredients to the wet sour cream mixture. Stir until a dough forms. Lightly flour a clean work surface. Place the dough on the floured surface and knead it until it is firm and smooth. Divide the dough into two equal halves. Take one half of the dough. Roll it out to an even thickness of 1/8 inch. Use a 3-inch biscuit cutter to cut the rolled dough into round shapes. To assemble the pierogi: Place a small spoonful of the mashed potato filling into the center of each dough round. Dip your finger in water and moisten the edges of the dough round. Fold the dough round in half, enclosing the filling. Press the edges together firmly with a fork to seal each pierogi. Repeat this process for all remaining dough rounds using the potato filling. Repeat the entire filling and sealing process with the second half of the dough, using the sauerkraut filling. To cook the pierogi: Bring a large pot of lightly salted water to a rolling boil. Carefully add the pierogi to the boiling water. Do not overcrowd the pot; cook in batches if necessary. Cook the pierogi for 3 to 5 minutes, or until they float to the top of the water. Use a slotted spoon to remove the cooked pierogi from the water. Serve hot.