Peel the bananas and cut them diagonally into slices about 5 mm thick. Fry the slices in hot oil until brown on both sides, remove and press flat (I`ve never seen the device for this in Europe, you can simply put the banana slice between two wooden boards and press firmly). Then put the approx. 2 mm thick slices again in the hot oil and bake until crispy. Take out, season with salt and you`re done.
Note: If you choose plantains that are yellow or that have already turned brown, the whole thing will be a little sweeter and taste more like banana.