I first made this peppery beef with a recipe from my boss, who lived in Korea in the 1950s. Freeze the ribeyes and slicing's a cinch. —Linda McCane, Chesapeake, Virginia
Freeze steaks until firm, about 30 minutes. Cut steaks crosswise into 1/4-inch slices. Sprinkle with sugar; place in a large resealable plastic bag. Add soy sauce, oil. sesame seeds, garlic, pepper sauce and pepper flakes; seal bag and turn to coat. Refrigerate 4 hours or overnight.
Thread beef onto 10 metal or soaked wooden skewers; discard any remaining marinade. Grill beef, covered, over medium heat 4-5 minutes on each side or until beef reaches desired doneness. If desired, sprinkle with green onions.