Heat 2 quarts (2L) water in a large pot over high heat until boiling. Add 2 tablespoons kosher salt , baking soda, and potatoes and stir. Return to a boil, about 10 minutes after returning to a boil.

When potatoes are cooked, drain carefully and let them rest in the pot for about 30 seconds to allow excess moisture to evaporate. Transfer to bowl with infused oil, season to taste with a little more salt and pepper, and toss to coat, shaking bowl roughly, until a thick layer of mashed potato–like paste has built up on the potato chunks.

Transfer potatoes to a large rimmed baking sheet and separate them, spreading them out evenly. Transfer to oven and roast, without moving, for 20 minutes. Using a thin, flexible metal spatula to release any stuck potatoes, shake pan and turn potatoes. Continue roasting until potatoes are deep brown and crisp all over, turning and shaking them a few times during cooking, 30 to 40 minutes longer.

add garlic and minced parsley. Toss to coat and season with more salt and pepper to taste. Serve immediately.