1
Preheat oven to 240°/220°C fan-forced. Line a baking tray with baking paper. Wilt the spinach in a saucepan of boiling water for 1-2 minutes. Pat dry.
2
Heat the olive oil in a frying pan. Add the onion and pepper and fry over a medium heat for 5 minutes. Next, add the spinach, sweetcorn, paprika, lemon zest and Tabasco sauce and cook until any water has evaporated. Season with salt and pepper.
3
Cut the sheet of pastry into four pieces. Spread the pesto all over each piece, leaving a 1cm border. Arrange the potato slices neatly to cover half of each piece, leaving a 2cm border all around the pastry.
4
Arrange the cooked vegetables on top of the potato, then add the grated cheese, if using. Brush the border with milk, then bring one side over to the opposite side, seal using your fingers and crimp the edges with a fork. Place on prepared tray.
5
Brush the top with a little more milk and cut three diagonal slits in each of the pastry turnovers. Bake for 25-30 minutes or until the pastry is golden brown and puffed. Serve with a dressed mixed salad.