Step 1) In a large mixing bowl, add brown sugar, soy sauce, sesame oil, red pepper flakes, ground ginger, corn oil, garlic and green onion. Mix well.
Step 2) Pour into a resealable plastic bag or baking dish. Add steak, turning to coat. Seal bag or cover dish; refrigerate at least 4 hours and or up to 24 hours.
Step 3) Remove meat from marinade; discard remaining marinade. Preheat grill to 400°F. Remove the meat from the refrigerator 30 minutes prior to grilling. Grill on each side 7 to 10 minutes and turn meat over.