700 g russet or Yukon Gold potatoes, medium bites (mehligkochend)
75 ml extra-virgin olive oil, duck fat, goose fat, or beef fat
Small handful picked rosemary leaves, finely chopped
Optional: 3 medium cloves garlic, minced
Freshly ground black pepper
Small handful fresh parsley leaves, minced
Instructions
Adjust oven rack to center position and preheat oven to 215°C.
Heat 2 liters of water in a large pot over high heat until boiling. Add 2 tablespoons kosher salt (about 25g), baking soda, and potatoes. Stir and return to a boil. Reduce to a simmer and cook until a knife meets little resistance when inserted into a potato chunk, about 15 minutes after returning to a boil.
Meanwhile, combine olive oil, duck fat, or beef fat with rosemary, garlic (if using), and a few grinds of black pepper in a small saucepan. Heat over medium heat, stirring and shaking the pan constantly, until garlic just begins to turn golden, about 3 minutes. Immediately strain oil through a fine-mesh strainer set in a large bowl. Set garlic/rosemary mixture aside and reserve separately.
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 the bowl with infused oil, season with more salt and pepper to taste, and toss to coat, shaking the 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, spread them out evenly, and roast in the preheated oven for 20 minutes without moving them. After 20 minutes, use a thin, flexible metal spatula to release any stuck potatoes, shake the pan, and turn the 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.
Transfer roasted potatoes to a large bowl and add the reserved garlic/rosemary mixture and minced parsley. Toss to coat and season with more salt and pepper to taste. Serve immediately.