Peel the sweet potatoes and slice them thinly.
Soak the sliced sweet potatoes in water for 10 minutes.
Add a suitable amount of cooking oil to a bowl and a pinch of salt.
Drain the sweet potatoes and mix them in the bowl so they are evenly coated with the oil.
Spread the sweet potatoes on a tray (oven or air fryer) so they are not overlapping.
Bake in the oven (or air fryer) at 210°C for 10 minutes, then flip and bake for another 5 minutes. Adjust temperature and time as desired.