Cook the bacon: In a skillet over medium heat, cook the bacon until crispy, about 3-4 minutes per side. Transfer to a paper towel-lined plate to drain excess grease.

Toast the bread: Lightly toast the bread slices in a toaster or on a skillet until golden brown.

Prepare the vegetables: Wash and dry the lettuce leaves. Slice the tomato into thin rounds.

Assemble the sandwich: Spread mayonnaise evenly on one side of each toasted bread slice.

Layer the ingredients: On two slices of bread, place the lettuce leaves, followed by tomato slices. Season the tomatoes lightly with salt and black pepper.

Add the bacon: Place 3 slices of crispy bacon on top of the tomatoes for each sandwich.

Complete the sandwich: Top with the remaining bread slices, mayo-side down. Press gently and slice in half if desired.