Cook the bacon in a skillet over medium heat until crispy, then place on paper towels to drain excess grease.

Mash the avocado and mix with mayonnaise and lemon juice to make a creamy spread. Add a pinch of salt and black pepper.

Lightly toast the bread slices with olive oil if desired.

Spread avocado mayo on the bottom slices of bread.

Layer lettuce, tomato slices, and crispy bacon over the avocado mayo.

Top with the other slices of bread, cut the sandwiches diagonally, and serve.