Add all the ingredients to a blender and puree for about 30 seconds.
Taste to adjust flavor and serve immediately.
Notes
Using a frozen banana leads to a creamier smoothie.
You can use fresh mango if you have some on hand.
Make sure to wash the spinach before making a smoothie.
To store: You can store the mango green smoothie for an extra day in the fridge but you'll have to give it a mix as the smoothie may separate in the fridge.
To freeze: Freeze the smoothie in an airtight container with some space on top as the smoothie will expand.