01 - Add the chopped apple, frozen banana, Greek yogurt, almond milk, maple syrup, vanilla extract, cinnamon, rolled oats (if using), and ice cubes to a blender.
02 - Blend on high speed until smooth and creamy, about 1 minute.
03 - Taste and adjust sweetness with additional maple syrup if desired.
04 - Pour into two glasses and serve immediately, garnished with a sprinkle of cinnamon or apple slices if desired.