01 - Preheat the oven to 425°F and prepare a large baking sheet by lining it with parchment paper or lightly greasing it.
02 - Place the potatoes in a large pot, cover with cold water, add kosher salt, and bring to a boil. Cook for 15 to 20 minutes until fork-tender, then drain thoroughly.
03 - Arrange the cooked potatoes on the baking sheet and gently smash each one to approximately half an inch thickness using the bottom of a sturdy glass or a potato masher.
04 - In a small bowl, combine olive oil, minced garlic, black pepper, and sea salt. Drizzle evenly over the smashed potatoes.
05 - Bake the potatoes for 20 to 25 minutes or until they develop a golden, crispy edge.
06 - Remove from the oven, drizzle melted butter over the potatoes, sprinkle grated Parmesan cheese on top, and return to the oven for 2 to 3 minutes until the cheese melts.
07 - Finish by sprinkling chopped fresh parsley over the potatoes and serve immediately.