I love D J Kirkby. She wrote a more than generous review of OLD MAN ON A BIKE. Now she offers to exchange soup recipes: her Lotus Land for my Jerusalem artichoke.
Proper stock is the first essential - none of those vile powders or stock cubes made from God knows what. Mostly I use chicken stock - though I keep vegetable stock in the freezer for vegetarian guests. Chop and melt two shallots and two cloves of garlic in unsalted butter. Meanwhile peel and slice the Jerusalem artichokes and simmer the Jerusalem artichoke peelings in the stock for twenty minutes to concentrate the flavour, strain. Add the artichokes to the onion and garlic and cook gently for a few minutes before adding the stock. Simmer until the artichokes are soft. Blitz with a blender till smooth. Check the seasoning. Reheat before serving and stir in the creme fraiche.
Guests tend to eat a second serving so prepare plenty or whip their bowls away quickly.