Toast the bread until golden brown and slightly crisp.
Spread mayonnaise on one side of each slice of bread.
On the first slice, layer lettuce, tomato, and turkey. Season tomato with a little salt and pepper.
Add the second slice of bread on top (mayo side down). Spread more mayo on the top of this middle slice.
Add bacon and an extra layer of lettuce or turkey if desired. Top with the final slice of bread, mayo side down.
Secure with toothpicks if needed and cut diagonally into halves or quarters.