Place potatoes in a large pot and cover with cold water. Season heavily with salt. Bring to a boil over high heat and cook until potatoes are completely tender, about 10 minutes after a boil is achieved. Drain in a colander and let rest for 10 minutes to dry and cool slightly.

Working one potato at a time, place potato on cutting board and smash firmly with the bottom of a heavy skillet to a thickness of about 1/2-inch thick. Transfer to a large plate or tray as you work.

Heat 1/2 cup oil in a large non-stick or cast iron skillet over medium heat until shimmering. Add as many potatoes as will fit in a single layer. Cook, shaking pan occasionally, until bottom side is deep golden brown, about 6 minutes.

Carefully flip with a thin metal spatula and cook until second side is golden brown and crisp, about 5 minutes longer. Transfer to a paper towel-lined plate and allow to drain.

Continue cooking potatoes in batches, adding more oil or fat as necessary, until all potatoes are cooked. Potatoes can then be left aside until ready to serve.

To serve, adjust oven racks to upper- and lower-middle positions and preheat oven to 400°F (200°C). Spread potatoes over two large rimmed baking sheets.

Transfer to oven and cook until heated through, about 6 minutes. Transfer to a large bowl, season to taste with salt and pepper, add herbs (if using), toss to distribute, transfer to a serving platter, and serve.