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 container.
02 - Blend on high speed until completely smooth and creamy, stopping to scrape down sides of blender as needed.
03 - Taste mixture and adjust sweetness or thickness by adding more honey for sweetness or additional milk for thinner consistency.
04 - Pour smoothie into glasses and enjoy right away for best texture and flavor.