Add cold water to the beet, bring to the boil and strain again. Add cold water again, season with salt, sugar, bay leaf, caraway and a little vinegar and cook rather briefly, i.e. not too soft (the beet should still taste nice and crunchy as an ingredient). Allow to cool and cut into fine strips.
Peel the onion and cut into rings. Peel the apple and cut into pieces.
Boil down the white wine with onions, apple pieces and bay leaves. Pour in soup, bring to a boil and then strain.
Add whipping cream and thicken with flour butter. Bring to the boil again briefly and season with salt, vinegar (finely acidic) and to taste with a little apple juice (rather sweet) and freshly grated horseradish (hot), but do not boil any more, as this can make the horseradish bitter.
Whip up with a hand blender and serve the apple-crisp soup with beetroot in hot soup cups or plates.
Add slightly warmed beetroot strips, pour in a dash of apple balsamic vinegar and stir once briefly with a spoon handle to get a nice marbling.