Preheat your oven to 350 degrees F. Line a large rimmed baking sheet (half-sheet size) with parchment paper.

In a food processor, combine the ricotta, Parmesan, minced garlic, parsley, basil, lemon zest, lemon juice, salt, and pepper. Process until smooth and well blended. Set aside.

On a lightly floured surface, unfold the thawed puff pastry sheet. Roll it out into a 10x14-inch rectangle. Transfer the pastry to the prepared baking sheet.

Using a sharp knife, score a border 1 inch from the edges, being careful not to cut all the way through. Prick the pastry inside the border all over with a fork to prevent it from puffing up too much.

Spread the herbed ricotta mixture evenly over the pastry, staying within the scored border. Arrange the tomato slices in a single layer on top of the ricotta.

Brush the exposed border of the pastry with the egg wash. This will give the crust a beautiful golden sheen.

Bake in the preheated oven for 25 to 30 minutes, until the puff pastry is puffed and golden brown, and the tomatoes are tender.

Remove from the oven and let cool slightly on the baking sheet. Cut into 6 to 8 squares. Serve warm or at room temperature. Garnish with extra fresh basil or a dollop of ricotta if desired.