Instructions

  1. Heat 2 tablespoons of the oil in a large heavy skillet over medium heat.
  2. Add onions & salt and cook, stirring often, until lightly browned, about 10 minutes. Transfer to a bowl. Wipe out skillet with paper towels.
  3. Add remaining oil to skillet & adjust flame to medium high.
  4. Pat steaks dry & add to oil. Leave them alone for for 4-5 minutes then flip & cook other side 3-4 minutes. Remove & wrap tightly in foil.
  5. Discard any remaining fat in skillet, return onions to pan & reduce temp to medium. Add garlic & cook 30 seconds.
  6. Add 1/2 cup vinegar, rosemary and brown sugar and cook, scraping up browned bits, until thick & syrupy, about 2 minutes.
  7. Unwrap steak & pour any accumulated juices in skillet along with remaining vinegar. Salt & pepper to taste.
  8. Slice steaks crosswise in 1/4 slices & serve topped with onions & sauce.