An irresistible vegetarian mushroom burger filled with melty mozzarella and slathered in homemade tomato relish. This is designed to be a low cost recipe. Preheat the oven to 180C/160C Fan/Gas 4.

Use vegetarian cheese to turn this into a delicious ... Put the chestnut and oyster mushrooms into a food processor in three or four batches and pulse each batch until finely chopped (or finely ...