Preparation

• 1
  With a sharp knife, score the tomatoes all around in a cross shape, cover in boiling water for a minute or two, then peel off the skin. Chop into small pieces, retaining any juice, and set to one side.
• 2
  Peel the onion and the carrot then very finely chop them both. Finely chop the celery too.
• 3
  Peel the potatoes and chop into very small dice.
• 4
  Heat the oil and butter together in a large heavy bottomed pan. Sauté the onion gently for 2 minutes then add the carrot and celery and continue to cook for another 10 minutes. Stir in a little cold water occasionally as you do so to make it creamy.
• 5
  Stir in the chopped tomato and potato and then add the hot beef stock; it should just cover the potato, add a little more water if not. Cook gently, stirring occasionally, for 10-15 minutes, or until the potato has softened and is just about cooked.
• 6
  Break up the spaghetti and add it to the pan, stirring in the rest of the cold water, about 200ml. Simmer for 10-12 minutes, making sure that the pasta is cooked.
• 7
  Stir in at least 50g of finely grated parmesan and season to taste with plenty of black pepper. Taste and add more cheese if needed, and add a little more liquid if it is too dry. Serve garnished with finely chopped parsley and extra parmesan.