01 - Preheat the oven to 425°F and line a large baking sheet with parchment paper.
02 - Place potatoes in a large pot, cover with cold water, add a pinch of salt, bring to a boil, then simmer for 15–20 minutes until fork-tender.
03 - Drain potatoes and allow to cool for 5 minutes before arranging them evenly on the prepared baking sheet.
04 - Gently press each potato with the bottom of a glass or potato masher until about ½ inch thick.
05 - In a small bowl, combine olive oil, minced garlic, salt, and pepper; drizzle mixture over the smashed potatoes evenly.
06 - Bake potatoes for 20–25 minutes until crisp and golden brown.
07 - Remove from oven, drizzle melted butter over potatoes, sprinkle Parmesan cheese evenly, and return to oven for 3–5 minutes until cheese melts and lightly browns.
08 - Transfer to a serving platter, garnish with fresh chives, and serve immediately.