Prep the Bread: Lightly toast the bread slices if desired, then spread a thin layer of mayonnaise on one side of each slice.
Build the Sandwiches: On four of the bread slices (mayonnaise side up), layer the heirloom tomato slices, sprinkling them with salt and pepper. Add the crispy bacon and lettuce. If using, sprinkle some fresh basil leaves for an extra touch of summer flavor.
Finish and Serve: Top with the remaining bread slices, mayonnaise side down. Cut each sandwich in half and secure with toothpicks if needed.
Pack for Picnic: Wrap sandwiches in parchment paper or place in reusable sandwich containers. Keep cool until ready to serve.
Enjoy with Pinot Noir: Pair these scrumptious sandwiches with slightly chilled Rombauer Pinot Noir.