Cook bacon until crispy, then drain and set aside. Toast all bread slices to your desired crispness, then let them cool slightly to prevent sogginess.

Wash and slice tomatoes and lettuce. Slice cheese if using.

Lay out all toasted bread slices on a large clean surface or multiple trays. Spread a thin layer of mayonnaise on one side of each slice.

For the bottom layer of each sandwich, place lettuce, tomato, and turkey/chicken on half of the bread slices. Top with a second slice of bread, mayonnaise side up.

On this second bread slice, layer bacon and cheese (if using). Top with the final bread slice, mayonnaise side down.

Secure each sandwich with four toothpicks, one in each corner, then carefully cut each sandwich into quarters, forming four triangles. Arrange on platters and serve immediately, or cover and refrigerate for a short period.