Pierogies for Christmas Eve - Mushroom Sauerkraut Pirogi

Pierogies have become part of our Christmas tradition. For Christmas Eve dinner my wife's family always has a meal inspired by their Polish heritage. On Christmas Eve we will have pirogi with potato filling, sauerkraut, and mushroom. For this recipe we made a mushroom sauerkraut filling but you can fill with anything. 

For the filling:

Sauté the onions in butter until about half done about 3 minutes. Then add the mushrooms and cook until all the moisture has left. When the mushrooms have cooked down add the sauerkraut and mix well. Cook for an additional 3 minutes.

For the dough:
Mix all the ingredients and knead until smooth.  Cover and let the dough rest for 30 minutes. Use a rolling pin to roll out the dough.  Lightly flour your rolling pin and working surface. The dough needs to be fairly thin. You can use a glass or cookie cutter to cut out circles. Put a small about of filling in the center of each circle fold over the edges and pinch together. We found a cheap tool at a kitchen store that makes this pretty easy. Add the pierogi in batches to salted boiling water and cook for five minutes. They will start floating to the top. We served with melted butter and dill on top.