These delicious babies are sometimes(incorrectly) called rosti potatoes. The secret behind their tastiness is that the cutting part way through increases surface area, which increases crunch. Crunch is always a net positive.
So being with smallish potatoes- I favor Yukon gold’s but red skinned ones work too, although they will never crisp up quite like older spuds. Lay your potato in the bowl of a wooden spoon, using a sharp knife make 5-6 vertical cuts. The bowl of the spoon will prevent you from slicing all the way through. Toss with some olive oil- by far the best way to do this is with your hands. Roast these puppies- they are flexible in that you can use a variety of temps and times. So work around your protein- if you are making a roast, they can go for 45 minutes at 350* They could also do 30 minutes at 400*. While they are piping hot- season with salt, pepper and microplaned garlic. Rosemary is good, too.