The Encyclopedia of Sandwiches. Makes one sandwich.
Pan-fry the bacon until just crisp. Drain on paper towels. Toast the bread lightly. Spread the mayonnaise on one slice of bread and the avocado on the other (or slice the avocado to layer on top). Layer the bacon, tomato and lettuce or arugula on top of one slice of bread and top with the other slice of bread. Cut sandwich in half on the diagonal and serve immediately.