Fry onion until translucent.
Reduce to moderate heat. Add garlic, allspice, peppercorns, caraway seeds and paprika. Let it fry for a few seconds. (Don't wait too long, paprika burns quickly).
Pour in the stock; add cubed potatoes, finely chopped cabbage and bay leaves. Cover with a lid, bring to gentle boil and cook for 20 minutes.
Add sausages, season with salt and continue cooking for 10 minutes.
Make a smooth, pourable mixture from flour and a small amount of warm water.
Pour the flour mix into the soup; stir continuously. Cook for an additional 5 minutes to allow the flour to thicken.
Take off the heat and stir in the double cream.
Add a splash of vinegar; stir to combine.
Try to find and remove peppercorn, allspice and bay leaves before serving.