For the chips with lemon and rosemary, wash and brush the potatoes, either peel them or continue to use them unpeeled. Cut the potatoes with a mandoline into 1 mm thin slices and dip these slices first in cold water and then rinse them in cold water until the water remains clear. Keep in cold water until further use.
For the seasoning salt, pound the salt, lemon zest and rosemary in a mortar and pestle to a uniform spice mixture. If salt is left over, simply store in a tightly sealed jar. It’s a good rub for a chicken or roast from the oven, and can also be sprinkled on baked potatoes.
For frying, heat oil to 160 °C. Check temperature with a potato slice: As soon as small bubbles form, the temperature is correct.
Drain raw potato slices and dry carefully between two dish towels. Add a small amount of potato slices at a time to the hot oil and stir to prevent them from sticking together.
Fry chips until they get some color and are dry.
Drain finished chips with lemon and rosemary each on cake paper and sprinkle with the flavored salt.