I've got two recipes here; the second recipe below was actually the first one I found; British, where "roasties" are a national staple. I've tried it, it wasn't particularly amazing but I suspect it takes some practice. The first recipe below is from Serious Eats, https://www.seriouseats.com/recipes/2016/12/the-best-roast-potatoes-ever-recipe.html, like everything on their website it has an exhaustive description of testing and results. I haven't tried it as of this writing.
SERIOUS EATS
Ingredients
Kosher salt
1/2 teaspoon (4g) baking soda
4 pounds (about 2kg) russet or Yukon Gold potatoes, peeled and cut into quarters, sixths, or eighths, depending on size (see note)
5 tablespoons (75ml) extra-virgin olive oil, duck fat, goose fat, or beef fat
Small handful picked rosemary leaves, finely chopped
3 medium cloves garlic, minced
Freshly ground black pepper
Small handful fresh parsley leaves, minced)
Instructions
1. Adjust oven rack to center position and preheat oven to 450°F/230°C (or 400°F/200°C if using convection). Heat 2 quarts (2L) water in a large pot over high heat until boiling. Add 2 tablespoons kosher salt (about 1 ounce; 25g), baking soda, and potatoes and stir. Return to a boil, reduce to a simmer, and cook until a knife meets little resistance when inserted into a potato chunk, about 10 minutes after returning to a boil.
2. Meanwhile, combine olive oil, duck fat, or beef fat with rosemary, garlic, and a few grinds of black pepper in a small saucepan and heat over medium heat. Cook, stirring and shaking 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.
3. 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.
4. 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.
5. Transfer potatoes to a large bowl and add garlic/rosemary mixture and minced parsley. Toss to coat and season with more salt and pepper to taste. Serve immediately.
Notes
Russet potatoes will produce crisper crusts and fluffier centers. Yukon Golds will be slightly less crisp and have creamier centers, with a darker color and deeper flavor. You can also use a mix of the two. The potatoes should be cut into very large chunks, at least 2 to 3 inches or so. For medium-sized Yukon Golds, this means cutting them in half crosswise, then splitting each half again to make quarters. For larger Yukon Golds or russets, you can cut the potatoes into chunky sixths or eighths.
BRITISH VERSION
Ingredients
1 kg (2.2 lbs) Maris Piper potato (Common potato in UK, similar to a Russet)
100 g (3-1/2 oz) duck or goose fat (for a luxurious taste), or 100ml / 3½ fl oz (7 tablespoons, .44 cups) olive oil
2 tsp flour
Maldon salt, to serve (a flaky sea salt)
Instructions
1) Put a roasting tin in the oven (one big enough to take the potatoes in a single layer) and heat oven to 200C / fan 180C / gas 6 (392 F).
2) Peel the potatoes and cut each into 4 even-sized pieces if they are medium size, 2-3 if smaller (5cm pieces). Drop the potatoes into a large pan and pour in enough water to barely cover them. Add salt, then wait for the water to boil. As soon as the water reaches a full rolling boil, lower the heat, put your timer on and simmer the potatoes uncovered, reasonably vigorously, for 2 mins. Meanwhile, put your choice of fat into the hot roasting tin and heat it in the oven for a few mins, so it’s really hot.
3) Drain the potatoes in a colander. Now it’s time to rough them up a bit – shake the colander back and forth a few times to fluff up the outsides. Sprinkle with the flour, and give another shake or two so they are evenly and thinly coated.
4) Carefully put the potatoes into the hot fat – they will sizzle as they go in – then turn and roll them around so they are coated all over. Spread them in a single layer making sure they have plenty of room.
5) Roast the potatoes for 15 mins, then take them out of the oven and turn them over. Roast for another 15 mins and turn them over again. Put them back in the oven for another 10-20 mins, or however long it takes to get them really golden and crisp. The colouring will be uneven, which is what you want. Scatter with salt and serve straight away.