Here, I peeled and sliced them. (When you do so, be prepared to get some sugary starch on your hands from the potatoes. It's a little difficult to get off, though vinegar and salt helped me scrub it off. Or wear gloves.) Then I placed them in an olive-oiled tray and roasted them.
When the potatoes are almost done, crush a bunch of garlic and grind some (toasted if you like) cumin and coriander. Cook the garlic, cumin, and coriander in some olive oil (or butter) and add to this some chili powder, cinnamon, and salt. This will form a sort of cooked-down paste, which you will then brush on the potatoes. Let the potatoes roast until done and enjoy!