Lay out steaks on a work surface, “nail” the garlic slices into the steak on both sides (about a clove per steak, more if you like).
Heat half of the olive oil in a skillet on medium heat. Place steaks in skillet and cook for 2 minutes on each side, turning once. Once cooked to desired doneness, remove steaks and any reserve juices from the skillet and set aside.
Add the remaining olive oil and sliced onions to the skillet. Sauté until golden then remove from skillet and set aside.
Pour the red wine into the skillet; scrape up the browned bits and simmer over medium-high heat until liquid is reduced by about half (this doesn't take too long). Return the steaks and onions to this skillet, season with salt and pepper, and cook another minute on both sides of steaks, until warmed through.
Serve steaks and onions on warmed crusty sandwich rolls.