Peel, chop and freeze the bananas the night before.
The next day, add all the ingredients to a food processor or a powerful blender and blend until smooth. Add more or less milk, depending on the texture you're looking for and how powerful is your machine.
Serve immediately with your favorite toppings. I added chopped walnuts, raisins, dried coconut chips, sliced banana and some peanut butter diluted with some almond milk.
Best when fresh, keep leftovers in an airtight container in the fridge for 1-2 days.