Home-made gnocchi with leek and tomato sauce. Cut a leek through the middle twice at right angles and then slice it to produce quartered rounds. Sweat this in a heavy pan with some oil, a chopped onion, a stick of chopped celery and a scored garlic clove. Five minutes or so, just to soften. Now add half a large jar of passata, or a can of diced tomatoes, stir it through the leek mixture and cook it gently for twenty minutes. Add a spoonful of water now and then if necessary. Meanwhile, make a big potful of gnocchi. The more I make home-made gnocchi, the worse supermarket versions taste, especially the shrink-wrapped ones. Years ago I used to buy these all the time, but nowadays I can boil and rice potatoes, add some flour and an egg (or no egg), roll it together, chop it into inches and throw the inches into a pot of boiling water faster than any supermarket trip, automated checkout or no automated checkout. ( Here's one using sweet potato.) Pour the cooked leek sauce ove