Preheat a griddle pan over medium-high heat.

Cook bacon on the preheated griddle pan until crispy, about 5 minutes per side.

Toast the bread until lightly browned.

Spread mayonnaise on one side of each slice of bread.

Arrange the bacon, lettuce leaves, and slices of tomato on one slice of bread. Top with the other slice of bread, mayo-side down.

Cut the sandwich in half and serve immediately.