01 - Preheat the 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, bring to a boil, then reduce to a simmer and cook 15 to 20 minutes until fork-tender.
03 - Drain potatoes and allow to cool for 5 minutes before arranging them on the prepared baking sheet.
04 - Gently press each potato using the bottom of a glass or potato masher until flattened to about 1/2 inch thickness.
05 - Combine olive oil, minced garlic, salt, and pepper in a small bowl. Drizzle evenly over the smashed potatoes.
06 - Bake for 20 to 25 minutes until the potatoes are crisp and golden brown.
07 - Remove potatoes from the oven, drizzle with melted butter, sprinkle with Parmesan cheese, and return to the oven for 3 to 5 minutes until the cheese is melted and lightly browned.
08 - Transfer the potatoes to a serving platter, garnish with fresh chives, and serve immediately.