Heat the butter in a medium saucepan. Fry onions until translucent.
Mix the apple, torn sauerkraut, bay leaves, juniper berries, peppercorns and wine well then simmer in a covered saucepan for 45 minutes. Check back every now and then ensuring there is enough liquid. If there is still liquid after the cooking time simmer with the lid removed but do not allowed it to get too dry. Remove bay leaves and serve.