Cut into ½ inch slices: 1 ½ lbs. fillet of beef
Pound the beef with a mallet until it is thin. Cut it into strips about 1 inch wide.
Melt in a pan: 1 tbsp butter
Sauté in the butter for 2 minutes: ¾ tbsp grated onio
Sauté the beef quickly in the butter for about 5 minutes. Turn it so that it will be browned evenly. Remove it. Keep it hot.
Add to the pan: 2 tbsp butter
Stir and sauté in the butter: ¾ lb sliced mushroom
Add the beef. Season it with: Salt and pepper, a grating of nutmeg, ½ tsp basi
Add and heat, but do not boil: ½ cup warm sour cream
Serve over pasta.