Preheat oven to 400 degrees. Line a rimmed baking sheet with foil. Lay bacon in a single layer. Bake for 18-20 minutes or until crisp. Transfer to a paper-towel lined plate. Cool and cut each piece in half.

Rinse and dry lettuce leaves. Cut tomato into thick slices.

Lightly butter each side of the bread and toast on a dry griddle or skillet over medium-high heat until golden brown. Arrange toast on a cutting board. Spread each slice of toast with 1 tablespoon mayonnaise.

Top one slice of toast with lettuce, tomatoes, and 4 pieces of bacon; repeat for second layer. Season with salt and pepper to taste. Place third piece of toast over top, mayonnaise side down. Repeat with second sandwich.

Cut sandwiches in half diagonally and serve.