Mix oil with pepper and use to baste both sides of steaks. Prepare sauce in a large skillet as follows: heat butter over medium high heat and sauté mushrooms and onions until tender. Add broth and wine and bring to a boil. Remove from heat.
Charcoal grill method for steaks: Grill steaks uncovered over medium hot coals to desired doneness. Turn steaks once halfway through grilling. When done, slice thin and smother with mushroom and onion sauté.