Quarter the fennel and discard the tough outer leaves and the hard core from each piece. Slice the rest of the flesh, including any little fronds.

Heat the butter in a saucepan and add the fennel, leeks and potato. Cook over a medium heat for about 5 mins, turning the vegetables over in the butter. The vegetables shouldn’t colour. Add a splash of water, cover the pan and cook the vegetables for 20 mins, stirring every so often. Add the stock or water and garlic, season, bring to the boil, then turn the heat down low and cover the pan with a lid or foil.

Cook for about 10-15 mins, until everything is completely tender. Stir in the cream and leave to cool. Purée in a blender until completely smooth. Check the seasoning and return the mixture to the saucepan – you can reheat it quickly just before serving. Ladle into bowls and scatter each one with the walnuts and cheese.