Preheat oven to 400℉. Line a 17x12 inch metal pan with parchment paper. Sprinkle shredded parmesan on the pan to form an even layer, covering the bottom of the pan.

Slice your potatoes lengthwise thin-about 1/8 inch thick (if they are too thick they won't roll easily and if they're too thin they will rip apart when you roll). Shingle the potato slices on the sheet pan, overlapping. Spray the tops lightly with olive oil spray, season generously with salt, onion powder and garlic powder. Bake for 20-25 minutes or until golden brown on edges. Remove from the oven and allow to cool only for 5 minutes.

Top the potatoes with the ham slices and then sprinkle evenly with the mozzarella. Start rolling tightly from the short side upwards towards the other short side. Reposition it on the baking sheet so that the seam side is down and tucked under the roll. Bake for another 7-10 minutes. Wait 5 minutes and then serve.

Garnish with fresh parsley + chili pepper flakes.