Preheat the oven to 425 degrees F.
Boil 'Em: Start by bringing a large stockpot filled with salted water to a roaring boil. Clean your potateos and place them in the boiling water. Boil them until they are fork tender, about 25 minutes depending on size.
Smash 'Em: When they are done boiling, drain them and run some cold water over the top so they are easier to handle. Spread the potatoes out on a parchment lined baking sheet, and using the bottom of a glass or a potato masher, smush them until they are thin and even. Do this for each potato.
Toss 'Em: Combine the olive oil, melted butter, garlic powder, parmesan and parsley in a bowl and drizzle it over the potatoes. Using your hands, mix the potatoes around on the baking sheet so that every piece is coated, front and back. Lightly sprinkle with salt & pepper.
Bake 'Em: Place the baking sheet in the oven and bake at 425 for about 25 minutes, then finish under the broiler for about 3-4 minutes, making sure to check frequently (every minute) to prevent burning! Option to sprinkle with extra parm and parsley, and enjoy!