Perioges (Messner/Steese style)

Here is the recipe for homemade perioges that we use:(by the way, it is in the Steese Cookbook if you have it)

2 c. sour cream (or plain yogurt)
5 c. flour
2 Tbsp. melted butter
2 eggs plus 1 egg yolk
2 tsp. salt
2 Tbsp. oil

Mix above ingredients and kneed into a soft pliable dough. Set aside and let rest at least 10 mins. Roll dough out approx. 1/4 in thick and cut into round circles (approx 6 in). Fill with desired toppings. (We use a mashed potato/cheese/onion mixture). Fold perogie in half; moisten edges with water and use fork to mash edges together, prevention potato mixture from escaping. Cook 6 pierogies at a time for 10 mins. in salted boiling water, removing with slotted spoon to cooking rack. Freeze individually. When ready to cook, fry in skillet with sliced onions and margarine or butter till golden brown.