01 - Combine banana slices, peanut butter, milk, sweetener, and vanilla extract in the blender.
02 - Incorporate ice cubes and a pinch of ground cinnamon into the blender if desired.
03 - Secure lid and blend on high speed until the mixture is smooth and creamy, approximately 30 seconds.
04 - Sample the blend, adjusting sweetness if necessary.
05 - Pour into two chilled glasses and serve at once.