1 Begin by making the beetroot stock. Grate the beetroot over a saucepan so none of the juices are wasted. Pour enough boiling water over the beetroot to cover it. Add the vinegar. Bring slowly to the boil, then take it off the heat and leave it to infuse while you prepare the rest of the dish.

2 In another saucepan, put the beef in with the water and the bouquet garni. Bring to the boil, skim and simmer slowly, covered for 1½ hours.

3 Next, wash the beetroot and shred it into a third saucepan (no need to remove the peel unless it's coarse). Add in the cider vinegar, tomato concentrate and the melted butter, plus 250ml of liquid from the stewing beef. Cover and simmer for an hour.

4 Peel and shred the other root vegetables. Fry them in two tablespoons of the butter or oil, until they are slightly golden, then tip them into the saucepan with the shredded beetroot. Simmer for 15 minutes, then season with salt and pepper.

5 Meanwhile, strain the meat, keeping all the stock. Rinse the saucepan and return the stock to the pan, and bring it to the boil. Add the cabbage and after 10 minutes, stir in the beetroot and vegetable mixture. Add the bay leaf and more seasoning if needed. You might like to add some ground cumin or caraway here depending on your preference and the time of year.

6 Mash the flour with the last tablespoon of butter and use it to thicken the soup. Finally, drain the beetroot stock from your first pan and add it to the soup just before serving. The soup should be very hot, at boiling point, so that no further reheating is needed once the stock has been added. Further boiling will only ruin the bright colour but not the flavour. Serve with the sour cream on the side.