Reheat Hungry Planet Chicken™ in a toaster oven, or hot pan until warm, about 2 minutes. Toss with barbecue sauce. Set aside.
Spread a thin layer of mayonnaise on both sides of the bread slices. Top a slice of bread with 1 slice of cheese, equally divide the barbecue Hungry Planet Chicken™ onto the bread with the cheese slice, top with another slice of cheese and a slice of bread.
Place in a pan on medium-low heat. Place a piece of aluminum foil on top of the sandwich and press down using a heavy skillet or pot (the aluminum keeps it clean).
After 2 to 3 minutes, flip when one side has become golden brown and crispy. Cook 2 to 3 more minutes then check for crispiness.
When both sides are golden brown, remove from pan, slice in half, and enjoy warm.