Colorful, flavorful heirloom tomatoes star in these classic sandwiches. Also try making a BLT salad: Stir the mayonnaise and pesto into 2 tablespoons of your favorite vinaigrette, then toss with lots of chopped lettuce, tomatoes, crumbled bacon or tempeh, and homemade croutons.
Lay the bread out on a work surface. Combine the mayonnaise and pesto in a bowl and spread evenly over 1 side of each bread slice. Season the tomatoes with salt and layer onto half of the bread slices. Top the tomatoes with bacon and lettuce, and cover with the remaining bread slices. Cut each sandwich in half on the diagonal and pile onto a platter.