Ultimate Crispy Roasted Potatoes

Bahan-bahan (6 porsi)

• 2 ½ pounds (1.1 kg) medium-sized Yukon Gold potatoes ((see Note 1))
• 1 large (12 oz / 340g) Russet potato
• Diamond Crystal kosher salt ((see Note 2))
• Freshly cracked black pepper
• ¼ cup + 2 tablespoons (84g) extra virgin olive oil, (plus a bit more for the rosemary)
• 1 heaping tablespoon (6g) fresh rosemary, ( finely chopped (optional))
• Fine sea salt ( for finishing (only as needed))