Preheat the oven to 350F and line 2 baking sheets with parchment paper.
Rinse the potatoes well. You may choose to either remove the peel or not.
Slice the potatoes using a mandoline slicer, a knife or a with the help of a food processor which has a mandoline accessory. Rinse them well under cold water, to remove some of the starch. Use paper towels to pat dry. You need to remove the moisture completely to get some crispy fat free potato chips.
Arrange the slices on the baking sheets making sure you don’t overlap them. Just place them close to each other.
Sprinkle salt and fresh rosemary.
Place the baking sheets inside the oven and cook for 20 minutes. Check from time to time to see if they don’t get burn.
After 20 minutes switch the place of the sheets so everything will cook evenly. Leave into the oven for another 20 minutes. Check your baked potato chips no oil and if everything is ok, you may cook for an extra period of 5 minutes. This will bring some more crunchiness to your snack.
Remove the sheet from the oven and transfer the chips to a bowl.
Serve and enjoy!