Wash and slice all the tomatoes. Slice the mozzarella.
TO MAKE THE PESTO:
Rinse or clean the basil well with water and dry with a paper towel. (If you need to store them: store them in a closed plastic bag with a slightly damp paper towel. As long as the leaves are dry they will stay green for several days.)
Combine the basil, garlic, and pine nuts in a food processor and pulse until coarsely chopped. With the processor running, slowly pour the olive oil (I used about a cup) into the bowl through the feed tube and process until the pesto is thoroughly pureed. Add the Parmigiano-Reggiano and puree for a minute. I also added the salt and pepper into the food processor but you can season later when serving.
Drizzle a little olive oil on the plate
Stack tomatoes and mozzarella (alternate each one according to the photo or however you wish)
Top with the pesto
Drizzle balsamic vinegar on top (and a dash of olive oil if desired), season with salt and pepper and top with freshly torn basil and pine nuts (optional)