Put the condensed milk in the can in boiling water and cook for 2 hours (it is best to use several cans at once, as it is very energy-consuming and the milk will keep for a long time even when it is boiled).
Crumble the biscuits into small pieces and place them in small bowls, glasses or similar.
Cut the bananas into small pieces and spread over the cookie crumbs. Spread the yogurt evenly over the top. Finally, carefully open the condensed milk can and let the now caramel-colored, viscous mass run over it.