Preheat & Boil:
Preheat oven to 450°F (230°C), or 400°F (200°C) with convection. Bring 2 quarts (2 L) of water to a boil in a large pot. Add 2 tbsp kosher salt, baking soda, and potatoes. Return to a boil, reduce heat, and simmer for about 10 minutes until a knife meets little resistance.

Infuse the Oil:
In a small saucepan, combine oil (or fat of choice), rosemary, garlic, and a few grinds of pepper. Cook over medium heat, stirring, until garlic just begins to turn golden (~3 minutes). Strain the oil into a large bowl and set the solids aside.

Coat the Potatoes:
Drain potatoes and let rest in the pot for 30 seconds. Transfer to the bowl with infused oil. Season with salt and pepper and toss vigorously to coat until a mashed-potato-like layer forms on the surface.

Roast:
Spread potatoes evenly on a rimmed baking sheet. Roast without moving for 20 minutes. Use a spatula to release stuck potatoes, shake and flip them. Continue roasting for 30–40 more minutes, flipping occasionally until deep golden brown and crispy.

Finish & Serve:
Transfer potatoes to a bowl. Toss with reserved garlic/rosemary mix and minced parsley. Season with additional salt and pepper to taste. Serve immediately.