Pierogies

Method

1. Mix the flour and salt. Add the egg, sour cream, and softened butter; knead just until smooth. Cover and rest for 30 minutes.
2. Boil the potatoes until tender. Drain well, mash with the cheese, season, and cool completely.
3. Roll the dough thin and cut it into 3-inch rounds. Add a spoonful of filling, fold, and pinch the edges firmly.
4. Boil in salted water until the pierogies float, then cook for 1 minute more. Drain and toss with onions browned in butter.