1 medium onion, diced
3 Tbsp. butter
2 cups mushrooms (fresh or canned), diced
1/2 tsp. salt
1/4 tsp. pepper
2 egg yolks
Saute the onion in the butter, until soft. Add the mushrooms, salt and pepper. Continue cooking for 10 – 15 minutes. Set aside. When cool, add a beaten egg yolk.
Cool thoroughly before filling the varenyky.