01 - Preheat oven to 425°F. Line a large baking sheet with parchment paper.
02 - Peel potatoes and cut lengthwise into 1/2-inch thick slices.
03 - Place each potato slice flat on a cutting board with two skewers or chopsticks on either side. Cut parallel lines 1/8-inch apart across the slice, stopping at the skewers. Flip and make diagonal cuts to create an accordion effect.
04 - Gently stretch each potato slice to open up the cut pattern.
05 - In a mixing bowl, combine olive oil, garlic powder, smoked paprika, thyme, parsley, salt, and black pepper. Brush both sides of each potato slice generously with seasoned oil.
06 - Place potato slices on the prepared baking sheet. Bake for 35–40 minutes, flipping once halfway, until edges are golden brown and crisp.
07 - In the final 5 minutes of baking, sprinkle with grated Parmesan if desired.
08 - Transfer potatoes to a serving platter and top with chopped fresh parsley before serving.