01 - Toast all 12 slices of bread until golden brown. Butter each slice lightly if desired for added richness.
02 - Spread mayonnaise evenly over one side of each toasted bread slice.
03 - Place 4 bread slices mayonnaise-side up on a flat surface. Top each with lettuce leaves and several tomato slices. Season lightly with salt and black pepper.
04 - Place a second bread slice mayonnaise-side up on top of each first layer. Arrange sliced chicken or turkey evenly, then lay 2 strips of cooked bacon over the meat on each sandwich.
05 - Top each sandwich with another layer of lettuce leaves. Place the final bread slice mayonnaise-side down to complete each triple-decker sandwich.
06 - Insert cocktail sticks through all 4 corners of each sandwich to hold the layers together. Using a sharp knife, cut each sandwich diagonally into quarters to form triangles.
07 - Arrange the triangle pieces on a platter and serve immediately with potato chips or dill pickles on the side if desired.