Preheat the oven to 400°F and spray two baking sheets with non-stick spray.
Wash and thinly slice potatoes, placing them in a large mixing bowl.
Add oil to the bowl and stir to coat the potato slices.
In a gallon-sized baggie, combine grated Parmesan cheese, garlic salt, and pepper. Zip the bag shut and shake to mix.
Spoon the potatoes into the cheese mixture and shake to coat them evenly.
Arrange the coated potatoes in a single layer on the prepared baking sheets and place them in the oven.
Turn the potatoes once during baking.
Once browned and fork-tender (approximately 40 minutes), remove them from the oven and enjoy with your favorite sauce, such as ranch dressing.