Jerusalem artichoke purée

Put the lemon juice and salt in a pan of water. Peel the artichokes and chop into rough chunks, dropping them into the pan as you go. Bring the pan to the boil and simmer the artichokes for 20-25 minutes, until easily pierced with a sharp knife. Drain well, then return to the pan and stir over the heat for a minute to evaporate any excess water.

Off the heat, add the butter, cheese and milk and, either with a hand blender or in a food processor, whizz until totally smooth. Season and add a few gratings of nutmeg. Adjust the consistency with a little more milk, if necessary. Finish with a drizzle of extra virgin olive oil and a scattering of chives.