1. Set the oven to 180°C/gas 4. Roll out the puff pastry into a 20x10cm rectangle. Crimp around the edges and prick the centre with a fork. Brush with a little beaten egg and bake for 12-15 minutes, until lightly brown. 2. Crumble the feta into a large bowl and add the onion, lemon zest, lemon juice, olives and seasoning. 3. Add the olive oil and basil and spoon the mixture into the centre of the tart. Bake for 2-4 minutes, until the cheese softens. 4. In the meantime, arrange the sliced tomatoes in a circle on a plate, season with sea salt and black pepper. 5. Separate the lettuce leaves and toss in a bowl with the olive oil and balsamic vinegar. Fry the leaves in a hot pan for one minute, until just wilted. 6. Transfer the wilted leaves to a salad bowl. Add the seasoned tomatoes and serve alongside the tart.