Heat the grill to 400 degrees while preparing the sauce.
Prepare the onion and wine sauce mixture
Heat large skillet over medium high heat for 3-5 minutes. Melt butter and toss in onions to caramelize. Each side should take 5-7 minutes to brown properly.
Grill the Steaks
Put steaks on the grill using direct hear. Grill time will depend on thickness of steak but should start checking after 5-7 minutes. I grilled mine to 135 degrees (medium).