To make dulce the leche, fill a large saucepan with sweetened condensed milk and water until the water is 2,5cm/1 inch above the can surface. Turn on the heat and boil. After the water boiled, simmer for two hours and a half over low heat. Then turn off the heat and let cool the can in the pot. After cool completely for a few hours, keep in the refrigerator.
Melt the salted butter. Set aside.
Crush the Oreos using a food processor. If you want to make it less sweet, only add half of the cream of the Oreos.
Once the Oreo crushed, turn off the food processor then pour the melted butter. Turn on the food processor again to mix the crushed Oreo and melted butter. Move it to a bowl. Set aside.
Whisk heavy cream and powdered sugar in a bowl until soft peak form. Let cool in a refrigerator.
Cut the bananas in ¼ of an inch. Set aside.
In a 300ml cup, put 1 tbsp the oreo crumbs, 4-5 cut bananas, swirl 1/2 tbsp dulce the leche, and 2 tbsp whipping cream, twice following with the order. Repeat the step to the other 4 cups.
Lastly, pour shaved milk chocolate on top.