Sauerkraut soup is best served with a glass of Gewürztraminer.
The base of this classic sauerkraut soup is homemade chicken stock. Get a cheap chicken carcass. I bought € 1,- worth of chicken bits and pieces at the market.
Heat the chicken carcass in the oven until lightly brown.
Add leek, carrot, onion, celery, thyme, pepper corns, bay leaf, mace and about 4 litres of water.
Don't boil but simmer the stock for 3 hours on a very low fire.
Strain the stock and reduce to two thirds. Add salt according to taste. At this point you could make a consommé but this will prove to be time consuming.
For two plates of sauerkraut soup you will need one litre of the chicken stock. Freeze the remaining stock for later use.
Add 150 grams of sauerkraut to the stock and simmer for 30 minutes. Remove the sauerkraut and use it for something else, like choucroute garnie.
In the meantime prepare the meat. Heat one rookworst in hot water. It pays off to buy a properly smoked butchers' rookworst instead of an industrial rookworst with smoke aromatics. If you live in Amsterdam Slagerij Zuid (Albert Cuypstraat 95) is the perfect address for smoked meats.
Fry 50 grams of cubed smoked pork cubes ('dobbelsteentjes') in a little butter. Drain the smoked pork on kitchen towel and set aside.
Cut the rookworst in slices and quarter the individual slices. Add the rookworst and smoked pork to the sauerkraut soup. Serve with a glass of Gewürztraminer.