1. Preheat the pizza oven by making a small fire at the back or on the side; add wood as needed to keep the fire going and allow the oven to reach the correct temperature*.
2. Working on a floured surface, divide the dough into 6 equal portions. Roll each piece of dough into a thin circle; spread a thin layer of chutney over the middle and arrange two slices of tomato (season with salt and pepper) followed by a few slices of onion and lastly a handful of cheese on one half. Fold into half-moon shapes. Seal the calzone by folding the lower edge slightly over the top edge and pinching closed. Use enough flour to prevent the calzones from sticking to the surface and tearing, but not so much that the dough becomes difficult to roll out.
3. Using a sharp knife, score the top of the calzone twice. Place a generous sprinkle of flour on your spatula before lifting the calzone and sliding it into the oven; place it on the opposite side to the fire. Bake for about 4 minutes until the bottom keeps its shape, then turn the calzone by 180° with the spatula and bake for another 4 minutes. It cooks quickly, so keep an eye on it; the cooking time will depend on how hot your oven is. Once the filling bubbles, it is usually ready. Serve hot straight from the oven.