In a large stockpot, over medium-high heat, add the oil and sauté the onion, apple, and potato for a few minutes. Add the white wine and reduce by half. Whisk in the flour until ýou have a smooth paste.
Add the sauerkraut, bay leaves, and vegetable stock. Reduce heat to medium. Season to taste with nutmeg, salt, and pepper.
In a separate pot, or in the microwave, warm the cream then add to the soup. Simmer for 30 minutes.
Remove bay leaves. Purée the soup, then pass it through a fine sieve. Add the caraway. Just before serving, add apple cider, lemon, and cabbage juice to give the soup a little extra kick. Garnish with croutons.