01 - Combine balsamic vinegar and honey (if using) in a small saucepan. Bring to a gentle boil over medium heat, then reduce to a simmer. Cook for 8-10 minutes, stirring occasionally, until reduced by half and syrupy. Remove from heat and let cool completely.
02 - Slice tomatoes and mozzarella into 1/4-inch thick rounds. Press a small heart-shaped cookie cutter into each slice to create heart shapes. Reserve trimmings for another use.
03 - Arrange heart-shaped tomato and mozzarella slices in alternating layers on a serving platter. Tuck fresh basil leaves between each layer.
04 - Drizzle the assembled salad with extra-virgin olive oil and cooled balsamic glaze. Season generously with sea salt and freshly ground black pepper.
05 - Serve immediately, garnished with additional fresh basil leaves if desired.