Freeze the banana ahead of the time you need to make the smoothie. If you can't, just add more ice when you blend.
Peel orange and squeeze onto the blender cup. Peel banana and add to the cup too.
Add oat milk and ice. Start adding spinach slowly until the blender cup is filled (I use a single serving blender for this). This is the time to add more ingredients as desired (additional sweeteners, protein etc).
Blend for a minute or two until smoothie is all blended and creamy. Adjust with more ice or few tbsps of water if needed. Blend again.
Serve in your favorite cup. Enjoy:)
Notes
Tips:
Add protein if you want to make it into a green protein smoothie.