Adjust oven rack to center position and heat to 425 degrees, or 400 degrees if using convection. (Convection is recommended, if available.) Combine potato chunks, 2 quarts water, baking soda and salt in a large saucepan.

Cut a 10-by-10-inch square out of cheesecloth and place bay leaves, peppercorns, garlic cloves and herb sprigs in the center. Gather up the corners of the cloth into a pouch, and tie off with butcher's twine. Add bundle to the pot with potatoes, and set over high heat. Bring to a boil, and cook until you can poke a knife into a larger chunk of potato without any resistance, about 10 minutes after the water comes to a boil.

Drain potatoes in a colander and discard aromatic bundle. Line a 13-by-18-inch rimmed aluminum baking sheet with parchment paper.

Transfer potatoes to a large bowl. Add melted butter and Parmesan. Season lightly with salt and pepper. Toss and fold with a rubber spatula until Parmesan, butter and starch form a slurry over the surface of the potatoes, about 30 seconds. Transfer potatoes to the prepared baking sheet and spread out so they are mostly separated from one another. (At this point, they can be allowed to cool, then transferred to a sealed container and stored in the refrigerator until ready to roast.)

Transfer baking sheet to oven and roast potatoes until pale golden brown and sizzling on the bottom, about 20 minutes. Flip potatoes using a thin metal spatula and continue roasting until crisp and blond-gold on most sides, about 15 to 20 minutes longer. (Check frequently toward the end, and don't allow the potatoes to cook beyond a deep gold, or they will turn bitter.)

Remove potatoes from oven and allow to cool for 5 minutes on the pan before transferring to a serving platter.