In a large mixing bowl, combine salt and water, whisk until the salt is dissolved. Add condensed milk and egg, whisking until combined.

In another bowl, combine flour and butter, rubbing together until no large chunks remain.

Gradually mix the flour mixture into the water mixture, kneading until absorbed. Cover with a cloth and let it rest for 15-30 minutes.

After resting, knead the dough again on a floured surface for about 5 minutes until it feels drier but still moist. Let it rest for another 10-15 minutes.

Coat your dough with a mixture of melted butter and oil, then divide it into 11 equal balls.

Let the dough balls rest for at least 3 hours, or refrigerate overnight.

On an oiled surface, roll out each dough ball into thin sheets, making sure they're large enough to hold your banana filling.

Place the banana filling in a square in the center of the dough sheet.

Fold the edges over the banana, creating little pockets. Cook them on medium heat in an oiled skillet until both sides are crispy and browned, about 4-5 minutes total.

(Optional) Add extra butter while cooking for a rich, indulgent flavor. Cut into pieces and drizzle with extra condensed milk or chocolate sauce, then sprinkle with sugar before serving.