Heat the oil in a large non-stick frying pan over medium heat. Cook the bell peppers for 5 minutes, or until tender and crisp. Add the mushrooms, oregano and a pinch of salt, and cook for about 4 minutes, or until the mushroom liquid has evaporated. Set aside.
Preheat a kettle or covered barbecue to high, with the hood closed. If using a pizza stone, place the stone onto the hotplate or grill rack before heating. Alternatively, lightly grease a 30 cm pizza tray or a large metal baking tray.
Place the pizza base on the stone or tray. Spoon tomato pasta sauce over the base. Add the bell pepper mixture and top with mozzarella; season with pepper.
Place the pizza on the hotplate or grill rack over indirect heat and close the hood. Bake for 15 minutes, or until the crust is brown and crisp, and the cheese is melted and bubbly.
Each serving provides 1314 kJ, 320 kcal, 18 g protein, 12 g fat (6 g saturated fat), 34 g carbohydrate (4 g sugars), 4 g fibre