01 - Add Greek yogurt, milk, avocado, banana, spinach (if using), honey or maple syrup, lime or lemon juice, vanilla extract, and ice cubes to blender canister.
02 - Blend on high speed until completely smooth and creamy, stopping to scrape down sides of blender as needed.
03 - Taste smoothie and adjust sweetness by adding more honey if desired, or thin with additional milk for preferred consistency.
04 - Pour into glasses and enjoy right away while chilled.