Creamy Sorrel Soup

Wash the sorrel leaves thoroughly in cold water, shake dry, then stack and roughly chop them. Dice the onion, slice the leeks, peel and cube the potatoes, and slice the garlic. In a small bowl, whisk together the crème fraîche and egg yolks until fully combined; set aside.

Melt the 50 g butter in a large heavy-bottomed saucepan over medium-low heat until the foaming subsides. Add the onion and leeks and cook, stirring occasionally, for 8–10 minutes until completely soft and translucent but not coloured.

Add the garlic and cook, stirring, for 2 minutes until fragrant.

Add the potato cubes and pour in the vegetable stock. Increase heat to bring to a gentle boil, then reduce to a simmer and cook for 15 minutes until the potatoes are completely tender when pierced with a knife.

Add the chopped sorrel to the pan and stir for 1–2 minutes until the leaves wilt and turn from bright green to olive-grey — this is normal and correct.

Remove the pan from the heat and use a stick blender to blitz the soup until completely smooth, about 2 minutes. Pass through a fine-mesh sieve for an extra-silky result if desired.

Return the pan to the lowest possible heat. Slowly ladle about 200 ml of the hot soup into the crème fraîche and egg yolk mixture, whisking constantly to temper it, then pour the tempered liaison back into the pan, stirring continuously. Do not allow the soup to boil from this point or the liaison will curdle.

Stir in the tablespoon of cold butter, season with salt, white pepper, and nutmeg, and warm over the lowest heat for 3–4 minutes until the soup is velvety and just steaming.

Ladle into warmed bowls, add a small spoonful of crème fraîche to each, and serve immediately with crusty baguette.