Step 1: Prepare the Puff Pastry

1. Preheat your oven to 400°F (200°C) and line a baking sheet with parchment paper.
2. Roll out the puff pastry on a lightly floured surface to smooth any creases, then transfer it to the prepared baking sheet.
3. Using a knife, score a 1-inch border around the edges of the pastry without cutting all the way through. This will help the edges puff up while baking.
4. Lightly brush the border with beaten egg to enhance its golden color.

Step 2: Prepare the Topping

1. In a small bowl, mix the olive oil, minced garlic, dried oregano, salt, and pepper.
2. Arrange the tomato slices evenly across the puff pastry, staying within the scored border. Overlap them slightly for a decorative look.
3. Sprinkle the shredded mozzarella and grated Parmesan cheese evenly over the tomatoes.
4. Drizzle the garlic-olive oil mixture over the top.

Step 3: Bake the Puff Pastry

1. Bake the prepared puff pastry in the preheated oven for 20-25 minutes, or until the edges are golden brown and the cheese is melted and bubbly.
2. Remove from the oven and let it cool for 5 minutes.

Step 4: Add Fresh Basil and Serve

1. Scatter the roughly chopped basil leaves over the top while the pastry is still warm.
2. Garnish with additional fresh basil leaves and a drizzle of balsamic glaze, if desired.
3. Slice into squares or rectangles and serve warm or at room temperature.