Place all of the ingredients in the blender in the order listed: almond milk, spinach, banana, mango, nut butter, and any extra mix-ins.
Blend until smooth. If you'd like it a bit thicker, add in a few ice cubes and blend again. Pour and enjoy!
If you are not using a high-powered blender such as a Vitamix, I recommend blending the spinach and almond milk first, then blending in the banana, then blending in the mango, nut butter, and any additional mix-ins.