Add all ingredients to a blender and blend until smooth.
Enjoy immediately.
Notes
Never forget how versatile smoothies are. Try adding a banana or other berry varieties to the smoothie. Add some spinach to get in your greens or add some carrot for a sweet taste. Replace the maple syrup with honey if that's what you have on hand. Trade in the walnuts for almonds if that's what's in your pantry. Go for something different every time you make a smoothie.
If using frozen fruit, there is no need to defrost. Simply add the frozen fruit to the blender in place of a couple of ice cubes.