01 - Preheat oven to 425°F. Place roasting tray with oil or fat inside to warm.
02 - Peel and cut potatoes into even 2-inch chunks.
03 - Place potatoes in large pot, cover with cold water, add 2 teaspoons salt. Bring to a boil, then simmer for 8–10 minutes until tender but firm.
04 - Drain potatoes and let steam dry for 2 minutes. Gently shake pot to roughen edges for enhanced crispiness.
05 - Carefully remove hot roasting tray from oven. Add potatoes and turn to coat evenly in oil or fat.
06 - Sprinkle with sea salt and pepper. Add rosemary sprigs and smashed garlic if desired.
07 - Roast for 40–45 minutes, turning once or twice until golden and crispy.
08 - Remove from oven, discard rosemary and garlic if used, and serve immediately.