Step 1

Remove the bitter stalk and leaves from the cauliflower, reserving the florets. Wash in a mixture of water with a dash of vinegar and set aside. Clean and slice the leeks.

Step 2

In a large, heavy pot, melt the butter then sweat the leeks in it until translucent but not brown. After 4-5 minutes, add the flour and stir together well until a smooth paste forms. Gradually whisk in the hot stock. Add the cauliflower florets, setting aside a few of the raw, smallest florets for decor. Bring to the boil.

Step 3

Cover, turn down the heat and leave to simmer gently for about 25 minutes.

Step 4

Towards the end of cooking, in a separate bowl, whisk the egg yolks with the cream, salt and pepper. Add a ladle-full of the soup's hot liquid and whisk together. Using a hand-mixer, blitz the soup until well blended. Gradually whisk in the yolk and cream mixture until the soup is smooth. Adjust seasoning if necessary.

Step 5

Serve topped with tiny raw cauliflower florets, chopped fresh chervil or parsley.