To make Pierogie Dough: Combine all ingredients and mix well. Knead dough on flat surface for approximately 5 to 7 minutes. Let dough rest for 30 minutes or refrigerate overnight; the dough can be kept in the refrigerator for up to 2 days.

Roll out dough into a thin sheet, approximately 1/4-inch thick. Then cut in circles: 2 inches for small pierogies and 3 1/2 inches for large pierogies. Fill circles with desired filling. Pinch the edges well and cook them in rapidly boiling water for approximately 10 minutes. Drain and serve immediately with butter. If you decide to store them, dip them in cold water, drain, and let them cool on a cookie sheet. When completely cool, store them in refrigerator.

To make Jalapeno Filling: Place potatoes in a saucepan and cover with cold water. Add salt, bring to a boil over high heat, and cook until potatoes are soft. When potatoes are done, melt the butter in a saucepan over medium heat. Add onion and saute until soft; you can continue cooking until onions are caramelized if you so desire. Drain the potatoes and mash them. Add the cooked onion and jalapeno and season with salt and pepper, to taste. Continue mashing until blended. Let filling cool. Use 1 tablespoon of filling to fill the circles of dough as directed above.