I have used refrigerated 2% milk. If you are hesitant to give refrigerated milk, boil the milk and cool it down to room temperature
I have used the Nestle Malted Milk powder. If you have Horlicks or something similar, you can use that. Read the ingredients and the allergen information if you are using the malted milk powder for your kid
Adjust the sweetener - Sugar/Honey - to taste. This is a good recipe to use up those ripe (browned) bananas which everybody is hesitant to eat. The quantity of sugar depends on the sweetness of the banana
I make it like milk shake, but if you like it thicker, reduce the quantity of milk