2 sheets frozen puff pastry, thawed
1/4 to 1/3 cup pesto
1 to 1 1/2 pounds mini tomatoes
6 ounces fresh mozzarella, chopped into small pieces
Olive oil for drizzling
Sea salt and freshly ground black pepper
1 tablespoon milk
6 to 8 leaves fresh basil, chopped
Preheat oven to 400 degrees F. Line baking sheets with parchment paper. Unfold sheets of puff pastry, cut each into thirds along fold lines then cut each third in half to create 12 rectangles in total and place on parchment. Lightly score edges of each rectangle to create 1/4-inch border then dock center with a fork.
Spread 1 to 1 1/2 teaspoons of pesto in center of each rectangle. Top with 6 to 7 mini tomatoes then fill in gaps with pieces of mozzarella (about 1/2 ounce). Drizzle lightly with olive oil and season with salt and pepper.
Whisk together egg and milk in a small bowl then brush edges of tarts. Bake for 18 to 20 minutes or until edges are browned. Top with basil and serve immediately.