Beerroot soup

Wash the beetroot carefully under the cold tap. Don't scrub, simply rub off any earth with your fingers. Don't damage the skin or cut the ends or it will bleed its colour during cooking. Put the beetroot into a pan, cover with water, bring to the boil, then reduce the heat and simmer, covered, for anything from 20 minutes to 2 hours depending on their size and age. The beetroot are cooked when the skins rub off easily. When cool enough to handle, rub off the skins and chop the beetroot.

Melt the butter in a heavy-bottomed saucepan over a medium-low heat. When it foams, add the onion. Season well, stir, then cover with a 'lid' made from baking parchment, putting the paper right on top of the onions. Cover the pan, turn the heat low and sweat over a gentle heat for 10 minutes. Meanwhile, bring the stock to the boil.

Add the beetroot to the onions with the stock. Season, then purée. Reheat, adding more stock or milk if you like, and adjust the seasoning.

Serve garnished with swirls of sour cream and chopped chives.