the best we've ever had.
Mix egg, warm water & oil. Beat with whisk. Add to flour & salt. Knead on floured surface until smooth. Divide into 2 parts. Cover & let sit 1 – 1/2 hours.
Boil potatoes & mash. Saute onions in butter. Add onions & cheese to potatoes & mash. Let cool.
Cut circles of dough & plop 1 Tbs of filling in middle. Fold & pinch sides.
Fill large pot with water & bring to boil.
Add 6 – 10 perogies & cook 8 – 9 mins, stirring occasionally. Remove with slotted spoon.