01 - Preheat oven to 425°F. Line a large baking sheet with parchment paper or lightly grease it.
02 - Place potatoes in a large pot, cover with cold water, add kosher salt, and boil until fork-tender, about 15–20 minutes. Drain thoroughly.
03 - Arrange cooked potatoes on the baking sheet. Gently smash each potato to approximately 1/2-inch thickness using the bottom of a glass or potato masher.
04 - Combine olive oil, minced garlic, black pepper, and sea salt in a small bowl. Drizzle evenly over the smashed potatoes.
05 - Bake potatoes at 425°F for 20–25 minutes until golden and crispy around the edges.
06 - Remove potatoes from oven, drizzle with melted butter, and sprinkle with grated Parmesan cheese. Return to oven for 2–3 minutes until cheese melts.
07 - Garnish with fresh chopped parsley before serving.