Discard the outer leaves of the cauliflower, then roughly break up the rest, including the stalk, and cut into manageable pieces.

Place the butter in a deep saucepan over a high heat. Add the onions and fry for a few minutes. Add the cauliflower and stock, and season well with salt and ground black pepper. Cover with a lid, reduce the heat and simmer for about 20 minutes until tender, stirring occasionally.

Remove from the heat and blend using a hand-held stick blender or food processor until smooth. Return the soup to the pan over a low heat. Add the cream, chives, mustard and nutmeg and stir well.

Check the seasoning, then serve piping hot with a few chopped chives to garnish.

Mary’s Tips: Can be made up to a day ahead. Freezes well.