Potato and Pea Pierogi

This recipe is based on one found in the Vegetarian Meat and Potatoes Cookbook.  I replaced some ingredients and as usual reduced the amount of oil used in the recipe. 

Filling:
1 1/ pounds russet potatoes, peeled and cut into chunks
1 teaspoons salt
1/2 tablespoon unsalted butter
1 cup frozen peas
1/4 teaspoons fresh ground pepper

Dough:
1 tablespoon flaxseeds
1 cup water
3 cups all purpose flour
1 teaspoon salt

1 tablespoon of oil will be needed per batch of pierogis for the final browning. 

1. Make the filling in advance.  Place the potatoes in a large sauce pan and cover with cold water.  Salt the water and bring to a boil.  Cook until tender, about 20 minutes.  Drain the potatoes, and mash them with a potato masher or ricer.  Set aside to cool.  Wipe the saucepan clean and return it to the stove.  Melt the butter in the saucepan and add the peas, cooking until warm.  Season with fresh ground pepper.  Remove from the heat and set the peas aside to cool. 
2. Make the dough while the potatoes and peas are cooling down.  Combine the flaxseed and the water in a bowl.  In a stand mixer fitted with a dough hook, combine the flour and salt.  Slowly add the water/flaxseed to the flour mixture with the mixer off, and then slowly turn the mixer on to the lowest speed allowing the dough to be kneaded until smooth.  
3. Divide the dough into 2 equal portions.  One at a time, roll the dough on a floured surface to about 1/8 of an inch thick. Cut into 3 to 4 inch wide stripes, and then cut across the stripes, to create 3 to 4 inch squares.  Put a heaping tablespoon of filing into on half of each square. Moisten the edges of the each square and fold over to form a triangle.  Press the edges together with a fork to seal.  
4. Bring a large pot of salted water to a boil.  Carefully add small batches of the pierogies to the water and boil them until the float to the service.  Place them on a towel to dry.  
5. Before serving, lighty brown the pierogies,  by heating up 1 tablespoon of oil (per batch) in a large skillet and browning each side of the pierogies.  
6. Serve with applesauce or sour cream

I will not be including the calories for this dish as the amount of oil needed to brown the pierogies will vary based on how many batches you make.