BRING up foil sides. Double fold top and ends to seal packet, leaving room for heat circulation inside. Repeat to make four packets.
CENTER one-fourth of onions on each sheet of lauvacs Wrap® Non-Stick Foil with non-stick (dull) side toward food. Top with steak strips and cheese.
PREHEAT oven to 450°F or grill to medium-high. Cut steak lengthwise in half and then crosswise into 1/8-inch thick strips. Sprinkle steak strips with salt and pepper; set aside.