Starter: Serves 4. Total time: 30 mins

A few months prior to the publication of Ann and Franco Taruschio's cookery book Leaves from The Walnut Tree, Recipes of a Lifetime (1993, Pavilion Books – and what a working lifetime that surely was), I happened to find myself in their kitchen. It was early one evening, just as Ann was spooning out small bowlfuls of this very soup for those who might fancy a taste.

The Walnut Tree was a unique restaurant in Wales, near Abergavenny, that they had opened "in the bitter winter of 1963" but, finally, and bitterly, once more, for so many admirers, decided to retire from in February this year. It was unusual to eat something there cooked by Ann, rather than Franco. But (forgive me Franco) that soup remains as one of my most vivid memories of eating at The Walnut Tree. The recipe that follows is taken directly from their book.

200g porcini, finely diced
5 medium potatoes
2 cloves garlic
60g butter
1 cup single cream
1-2tbsp finely chopped parsley
freshly grated Parmesan cheese
1 white truffle, shaved (optional)
salt and freshly ground black pepper

Peel and roughly chop the potatoes, boil them in salted water with the garlic. Leave the potatoes to cook until they disintegrate. Pass the potatoes, cooking water and garlic through a food mill, return to the heat. Add half the butter, salt and freshly ground pepper. Beat the mixture with a balloon whisk; if the mixture is too thick add some more water.

A few minutes before serving, add the porcini mushrooms which have been sautéed in the remaining butter, the cream and parsley. Check the seasoning. Serve with Parmesan cheese and shavings of white truffle if available.