Combine the frozen banana slices, peanut butter powder, almond milk, Greek yogurt, vanilla extract, and sweetener in the jar of a high-speed blender.

Add ice cubes to the blender jar.

Secure the lid and process on the highest speed setting for approximately 45 to 60 seconds until the mixture reaches a uniform, creamy texture.

Perform a visual check for unblended ice or fruit chunks.

Pour the contents into a glass and serve immediately to maintain optimal viscosity and temperature.