Mash the banana in a bowl with the sugar until it's smooth with not many lumps. Add to a saucepan under a low heat and stir until the sugar has dissolved and the banana is hot. Gradually add in half of the milk until it starts to steam, remove from the heat and add in the cinnamon, stir.
Add the banana milk to a blender and blend until completely smooth whilst gradually adding the other half of the milk. (A high power blender is best to ensure no lumps remain)
Divide the hot coffee into two mugs and top with the banana milk (use a sieve when pouring the milk if you don't have a high power blender). Top with an extra dusting of cinnamon is desired.
Notes
It's best to use a very ripe (almost completely black) banana for this.If you don't have a high power blender try using a sieve when pouring the milk into the cups to ensure there are no lumps.These glasses are similar to the ones I used and are really cute, perfect for hot chocolates, lattes or Irish coffees!*Please note all imperial measurements are an approximate.