Preheat the oven to 400°F and line a baking sheet with parchment
Slice the potatoes thinly on a mandoline and soak in cold water for 10 minutes
Whisk together the 00 flour, Parmigiano, cold water, olive oil, salt, and rosemary until smooth
Add the potatoes into the batter and coat them well
Sprinkle the baking sheet with semolina and olive oil
Spread the mixture evenly on the baking sheet in a thin layer and top with more semolina and olive oil
Bake for 1 hour and 15 minutes, switching the tray from the bottom to the top rack halfway through
Broil for a few minutes at the end to crisp the top
