Place a potato on its flattest side on a cutting board. If your potato is too unstable, slice a thin piece off the bottom to prevent it from rolling. With a thin knife, cut slices into the potato, being careful not to cut all the way through.
Alternate the slices of butter and Parmesan, stuffing them between the potato slices. Season the potato with garlic powder and salt. Drizzle with olive oil. Bake for 45 minutes.
Remove from oven and drizzle heavy cream. Top with cheddar cheese. Bake for an additional 10-12 minutes more, until cheese is bubbly and browned.