This is a common Chinese dish you see at Chinese fast food places like Pick Up Stix, PF Changs, and Panda Express, where it is called Mongolian Beef or Angus beef with black pepper.
This serving for one, recipe:
2T oil
half onion
1 c beef, cross-grain sliced
2 green onions
1/4c water
1 clove garlic
2 T oyster sauce
2 T soysauce
1 t sugar or substitute
1/3 t black pepper