Braendenaeldesuppe

There's a week in late March when the verges around Copenhagen turn. You walk past a hedge you've seen grey and empty all winter and suddenly there are nettles pushing up, bright and urgent, the first green thing to announce that the cold has let go. This is the week braendenaeldesuppe comes back to the kitchen.

Nettle soup is spring tonic food, the kind Danes have been making for as long as anyone can remember. When the cellar was empty of root vegetables and the garden hadn't started, nettles were already there: wild, free, and full of everything a body needed after a long winter of salted pork and preserved cabbage. We still make the soup, not because we need the vitamins the way our grandparents did, but because the body remembers. The first spoonful of nettle soup tastes like the year turning.

What you want are the top four or five leaves of young plants, no more. Older leaves go stringy and bitter. Wear gloves when you gather them and a long sleeve, and trust the sting: it disappears the moment the leaves hit hot water. I'll walk you through the blanch that saves your mouth, the off-the-heat blend that saves the color, and the eggs that turn the whole thing from a puree into a proper bowl. The season decides when you make this one. Late March, into April, while the leaves are still small and the light is still new. You'll know when it's right.