Apple Oat Milk Shake is very well suited as a quick healthy breakfast. For the apple oat milk shake first fill quark with well chilled milk into a blender. Add the oat flakes. Core an unpeeled apple, cut into coarse pieces and put into the blender. Mix until the apple oats milk shake froths up and becomes creamy. The oat milk shake does not need to be sweetened because the apple already contains fruit sugar.