The flat iron steak is a tender cut that, surprisingly, comes from the front shoulder where most of us think about tougher cuts and long cooks required to produce tender finished products.  Today, I'm using a flat iron steak from a bull elk.  This can be done with any venison, but the larger species are generally better as you need to split the steak along a tendon that runs the length of the steak.  If you do this on a small deer, your resulting steak can be thin.  This is a straightforward recipe with nothing more fancy than marinade and grilling the steak to a perfect medium rare.