Peel and chop 2 ripe bananas into small pieces.
In a blender, add the chopped bananas, 500 ml of cold milk, and 2 tablespoons of sugar (optional, adjust according to taste).
Blend the mixture until smooth and creamy. If you prefer a thinner consistency, add more milk.
Pour the banana milkshake into glasses and serve immediately. You can also add a few ice cubes if you prefer it extra cold.