01 - Place bananas, cold milk, maple syrup or honey, vanilla extract, and ice cubes in the blender jar.
02 - Blend on high speed until the mixture becomes smooth and frothy, about 30 seconds.
03 - Taste the shake and increase sweetener if desired.
04 - Divide the shake evenly between two chilled serving glasses.
05 - Top with whipped cream, banana slices, and a sprinkle of cinnamon if using. Serve immediately.