Preheat the oven to 375°F and position a rack in the center of the oven.
Wash and trim the potatoes as needed. Cut the 5–7 medium russet potatoes into 1/4‑inch‑thick fries, keeping the pieces as uniform in size as possible.
Place the cut fries in a bowl of cold water and soak for at least 20 minutes to remove excess starch.
Drain the fries and dry them thoroughly with clean kitchen towels or paper towels so they are as dry as possible.
In a large bowl, combine 2 tablespoons olive oil, 2 teaspoons garlic powder, 1/2 teaspoon salt, and 1/4 teaspoon black pepper. Add the dried fries and toss until evenly coated.
Add 3/4 cup freshly grated Parmesan cheese to the bowl and toss the fries so the cheese coats them evenly.
Arrange the coated fries in a single layer on a baking tray (do not let them touch) so air can circulate and they can bake evenly.
Bake for 25–35 minutes, flipping the fries once about halfway through baking, until they are golden and crispy. Oven times vary, so watch closely toward the end of the cooking time.
Remove the fries from the oven and let them cool slightly to crisp up. Sprinkle with finely chopped fresh parsley if desired, and serve hot.