Brush steak with olive oil. Season liberally on both sides with salt and freshly ground black pepper.
Preheat grill. Add steaks and cook 4-5 minutes per side for medium rare, turning 90 degrees halfway to mark.
While steak is grilling, prepare mushrooms. Melt butter in a large straight-sided sauté pan over medium high heat. Add garlic and keep it moving until golden. Add onion and mushrooms and cook, tossing occasionally, until mushrooms are as browned as you like.
Serve steaks with sautéed mushrooms and desired sides.[[Category:Sautéed recipes]