Jerusalem Artichoke Soup

January. The garden is bare and the light goes by four. The kitchen window has fogged over and there's something on the hob that smells of butter and earth and quiet warmth. This is Jerusalem artichoke weather.

They're not much to look at. Knobbly, muddy, the shape of ginger root after a bad day. They peel badly, discolour the moment you turn your back, and resist every attempt to make them look respectable. None of that matters. What matters is what happens when you cook them slowly in butter and good stock and blend them into a soup so silky, so deeply nutty and rich, that it feels like winter's single best argument for itself.

I find them at the market in late November and buy them through to February, when they start to lose their sweetness. The stallholder piles them in a crate without ceremony. No one queues for Jerusalem artichokes the way they do for the first asparagus or the summer tomatoes. That suits me. More for the rest of us.

The soup is simple. Artichokes, butter, onion, stock, cream, lemon. A scattering of toasted hazelnuts if you want a bit of crunch, though it's not compulsory. I wrote it down in the notebook years ago: "artichoke soup, Tuesday, fog outside, best thing all week." I've made it dozens of times since and the note still holds. There are few better feelings than putting a warm bowl of this in front of someone on a cold evening and watching their shoulders drop.