Step 1: Preheat and Prepare : Preheat your oven to 400°F (200°C). Line a baking sheet with parchment paper.

Step 2: Prepare the Puff Pastry : Roll out the puff pastry sheet on a lightly floured surface. Cut it into 12 equal squares (about 2½ inches each). Place the squares on the prepared baking sheet. Lightly brush the edges of each square with the beaten egg for a golden finish.

Step 3: Assemble the Bites : Add a small piece of mozzarella in the center of each pastry square. Top with a half cherry tomato, cut side up. Drizzle lightly with olive oil, and sprinkle with salt and pepper.

Step 4: Bake : Bake for 15–20 minutes, or until the pastry is puffed and golden brown. Remove from the oven and let cool slightly for 5 minutes.

Step 5: Prepare the Balsamic Glaze (while baking) : In a small saucepan, combine balsamic vinegar and brown sugar. Simmer over medium heat for about 8–10 minutes, stirring occasionally, until thickened and reduced by half. Remove from heat and let cool — it will continue to thicken as it cools.

Step 6: Add Fresh Basil and Drizzle : Once the bites have cooled slightly, place a fresh basil leaf on top of each. Drizzle with balsamic glaze before serving.