Over high heat, bring balsamic vinegar to a boil in a saucepan. Lower heat to medium and simmer for about ten minutes, or until it has slightly thickened.
Remove from heat and let cool.
On each toothpick, place one tomato, one basil leaf, and one mozzarella ball.
Using a spoon, drizzle cooled balsamic reduction on top.
Recipe by The Gingham Apron at https://www.theginghamapron.com/caprese-salad-skewers/