Remove the cores from 375 g (13 oz) ripe roma (plum) tomatoes, then chop them finely by hand or in a food processor. Add 10 finely chopped basil leaves, 4 crushed garlic cloves, 4 tablespoons tomato passata and 1 tablespoon olive oil. Mix well and leave to stand for 30 minutes to allow the flavours to infuse. Season with salt and pepper. This makes enough sauce for two 30 cm (12 inch) pizzas.