Cut the potatoes into slices, halve the onion and cut into slices (on the slicer on level 2).
Mix both together, season properly with pepper and salt.
Heat the oil in a non-stick pan and pour in the potato and onion mixture. Fry for 1 - 2 minutes over high heat (do not stir), pour a small sip of water over it, put the lid on and cook for 25 minutes over medium heat with the lid always closed. The potatoes are allowed to add a bit.