Preheat grill to high.
Cut 1 bagel in half and toast under grill for 1-2 minutes. Keep an eye on the bagels to ensure they do not burn.
Thinly slice half a tomato and mozzarella.
Layer tomato and mozzarella on the toasted bagel. Drizzle over 1 tsp of balsamic vinegar and olive oil. Top with basil.