Pan Seared Sirloin Steaks with Sauteed Onions by John Spottiswood

We don't eat a lot of steak, and when we do I normally grill it. My mom used to frequently serve pan seared steaks, generally cheaper cuts like sirloin or london broil. So I thought I'd give it a try and see if I could come up with something competitive with my grill. I started with a base recipe from Cook's Illustrated, and…