Place the potatoes in a large pot and cover them with enough water so that the water line is 2 to 3 inches above the potatoes. Add 1 tablespoon of kosher salt to the water and bring to a boil.
Boil the potatoes for 18 to 20 minutes or until a fork easily pierces the potatoes. Drain.
Meanwhile, preheat the oven to 425 degrees F.
Spread the drained potatoes out on a large baking sheet and cut any extra long ones in half so that most of the potatoes are similar in size.
Using a measuring cup, glass, fork, or potato mashed, firmly press down on each potato until they are about 1/2 an inch thick and the skins have cracked.
Mix together the melted butter, salt, garlic powder, and pepper. Generously brush each potato with the butter mixture.
Transfer the baking sheet to the preheated oven and roast for 30 to 40 minutes depending on your preferred crispiness.
While the potatoes are roasting, mix together the parmesan and parsley.
As soon as the potatoes come out of the oven, top them with the parmesan parsley mixture. Serve warm.
Notes
Freshly grated parmesan or Parmigiano-Reggiano is suggested for this recipe. To make it easier, cube the block of cheese and run it through a food processor until it resembles coarse crumbs. Store the extra in the fridge for up to 2 weeks.
Store the potatoes in an airtight container in the fridge for up to 4 days.