Turn the oven on to 200°C/400°F/gas mark 6 and cut a piece of baking paper to fit a baking tray. Using the bridge cutting technique, cut the tomatoes in half – hold a tomato between your thumb and finger on a board and put the knife under the bridge and cut downwards. Repeat with the other tomatoes.
Grate the cheese – hold the handle of a grater with one hand and then push the cheese downwards over the grater teeth. Always keep your fingers away from the grater teeth as they’re very sharp!
Cut the pastry sheet into 6 even squares – start by cutting it in half down the middle (lengthways) and then cut each half into 3. Sit the pastry squares on the baking paper on the tray.
Spoon a tablespoon of grated cheese on each of the pastry squares, put the tomato halves cut side facing upwards down the middle from one corner to another. Sprinkle over the herbs and a little freshly ground black pepper.
Pick up 2 opposite corners of a pastry square and fold over in the middle, sitting one corner of the pastry on top of the other and press to make sure that they seal together. Repeat with the other pastry squares.
Using oven gloves put the tray into the oven for 20 minutes until the pastry is cooked and golden. Leave to cool slightly, eat while still warm.