Preheat oven to 400°F and lightly grease a baking sheet.

Unfold the puff pastry on a lightly floured surface.

Roll out the puff pastry into a 12-inch square.

Crimp the edges of the puff pastry or gently fold over 1/2 inch of the edge to create a border.

Spread pesto evenly over the top of the puff pastry, leaving the crimped edges bare.

Sprinkle shredded mozzarella cheese over the pesto.

Arrange thin tomato slices on top of the cheese.

Sprinkle the remaining cheese over the tomato slices.

Bake in the preheated oven for 17 to 20 minutes, or until the crust is golden brown and the cheese is melted and bubbly.

Let the tart cool slightly before slicing and serving.