Recipe - Pierogi Fillings Meat

1 One half pound Ground beef or ground beef
and pork
2 lg Onions (finely chopped)
One half pound Butter, divided
Salt and Pepper to taste
1 cup Chopped mushrooms (optional
4 tablespoon Sour cream (optional)

Saute meat in 1/3 of butter till almost fully cooked. (Meat should not be
overcooked.) Drain. Use balance of butter and saute onion till crystal
clear. Add meat, seasonings and optional ingredients to taste. Let mixture
cool.