01 - Preheat oven to 425°F. Line a large baking sheet with parchment paper.
02 - Place potatoes in a large pot, cover with cold water, add a pinch of salt, and bring to a boil. Reduce heat and simmer for 15 to 20 minutes until fork-tender.
03 - Drain potatoes thoroughly and allow to cool for 5 minutes. Arrange evenly on the prepared baking sheet.
04 - Using the bottom of a glass or potato masher, gently press each potato until about 1/2 inch thick.
05 - In a small bowl, combine olive oil, minced garlic, sea salt, and black pepper. Drizzle mixture evenly over smashed potatoes.
06 - Bake for 20 to 25 minutes until edges are crisp and golden brown.
07 - Remove potatoes from oven. Drizzle with melted butter and sprinkle with Parmesan cheese. Return to oven for 3 to 5 minutes until cheese melts and browns lightly.
08 - Transfer potatoes to a serving platter, garnish with fresh chives, and serve immediately.