Stir Fry Beef with Peppers

I was planning to cook something completely different for dinner, but this Pioneer Woman recipe jumped out at me as I was scanning my google reader this morning.  I had to make a special trip to the store for the beef, and had to figure out what to substitute for sherry (red wine vinegar),  but it was so worth it.  I also threw in some of those haricot verts and left out the red pepper flakes.  Anyway, make this for dinner.

I'll let you read PW's recipe, because it's perfectly detailed with pictures.