Authentic Polish Pierogi with Potatoes and Cheese

Place potatoes in a pot, cover with water and cook until fork tenderIn the meantime heat up the oil or ghee in a frying pan, add onions and cook until golden brownOnce potatoes are cooked, using a hand blender or potato masher, mashed potatoes so they don't have lumpsAdd farmers cheese and mix togetherAdd onions, other cheeses, spices, salt and pepper and mix well.Pour the flour on a counter or other surface that will allow you to make the doughAdd a pinch of saltMake a little whole in a middle and start adding milk and butterAdd a little water at the time and work the dough until you can form a ball about 10-15 minutesOnce done, cover it with the big bowl and let it rest for about 20-30 minutesRoll the dough until thin (like pasta) and using either cookie cutter or large wine glass cut the circlesPlace 1 teaspoon of fling in the middle of the circleWet one half of the circle and then seal it togetherBoil large pot of water and season with saltOnce the water is boiling put about 8 pierogi at the timeOnce they come to the surface let them cook for 1 minute and using spider or slotted spoon take them out on a plateIf you want to fry them like I did here, use 1 tablespoon of oil or ghee and fry pierogi on each side until golden brownUsing separate pans add oil and onions and fry the onions until golden brown and bacon until crispy (you don't need fat for bacon as it is already fatty)Add onions and bacon on top with pierogi and serve with sour cream