01 - Toast all 6 slices of sandwich bread until golden brown and slightly crisp.
02 - Spread mayonnaise evenly over one side of each toasted bread slice.
03 - Place 2 slices of toast mayo-side up on a clean work surface. Layer each with half of the turkey or chicken breast, 1 slice of ham if using, and 2 strips of bacon.
04 - Top the meat layers with sliced tomatoes and iceberg lettuce leaves. Season generously with salt and pepper.
05 - Place a second toasted bread slice mayo-side up on top of each assembled layer to form the middle tier.
06 - Repeat the layering process on each sandwich with the remaining turkey or chicken, ham, bacon, tomato slices, and lettuce.
07 - Finish each triple-decker sandwich with the third toasted bread slice, placing it mayo-side down on top.
08 - Insert 2 toothpicks into each sandwich to hold the layers together. Using a sharp knife, cut each sandwich diagonally into quarters to create classic wedge-shaped servings.
09 - Serve immediately while the toast is still warm and crisp. Pair with potato chips or a fresh side salad if desired.