1 can chunk tuna (drained)
2-3 tablespoons mayonnaise
2-4 slices red onion (diced)
1 Golden Delicious or Granny Smith apple (diced)
2-4 slices Cheddar cheese
Mix tuna, mayonnaise, onion and apple. Place a slice of lettuce (if using) on 1 piece of bread, then spread with tuna. Top with cheddar cheese. Repeat with remaining sandwich ingredients. Broil open face and serve.