During summer, tomatoes are tasty and plentiful, but out of season, tinned plum tomatoes will give a better flavour. Use olive oil, onion and garlic to add depth and intensify the sauce with tomato purée. The sauce can be stored in a jar in the fridge for up to ten days. Toss it simply with pasta or use it to make a good bolognese sauce. Alternatively, you could add chopped black olives and parsley to the sauce and bake it with chicken, or layer slices of aubergine and Mozzarella, top with the sauce, finish with plenty of grated Parmesan and pop in the oven for an aubergine Parmigiana.