Roll the pastry out on a lightly floured work surface to form a rectangle 25 x 35 cm (10 x 14 inches). Using a sharp knife, score a 2.5 cm (1 inch) border around the edges. Transfer to a baking sheet and spread the pesto over the pastry.
Arrange the tomatoes and feta over the top and scatter over the Parmesan. Season with salt and pepper. Bake in a preheated oven, 220°C (425°F), Gas Mark 7, for 20 minutes until the pastry is puffed and golden. Remove from the oven and scatter over the basil leaves.