Put the elderberry juice in a saucepan with the water. Add the cloves, the cinnamon stick and the sliced vanilla pod in a spice sachet. I use a tea filter bag for this. Mix the packet of pudding powder with the sugar and stir into the soup. Bring the soup to the boil briefly so that the pudding does not thicken it too much. Remove the spice sachet and serve the soup. Break the rusk into pieces and place on the soup plate.