Add the low-fat Greek yogurt, vanilla extract, frozen banana, light coconut milk, vanilla protein powder, and ice cubes to a blender.
Blend on high until smooth and creamy, stopping to scrape down the sides if needed.
Adjust thickness by adding more ice for a thicker shake or a little water (or more coconut milk) for a thinner consistency, then blend briefly to combine.
Pour into two glasses and serve immediately.
Notes
Use a ripe frozen banana for best texture and sweetness.
Adjust protein powder amount to taste or dietary needs.
Light coconut milk keeps it lower calorie while remaining creamy.