Preheat the oven to 375. You'll need an oven proof casserole dish with lid.
Scrub the potatoes under cool, running water until the skins are clean, and place them in the casserole dish.
Add the chopped onion and stir.
Sprinkle the fresh rosemary and oregano leaves (or dried) onto the potato and onion mix, then stir it.
Add the olive oil, giving it one final stir, then add a dash of salt and pepper.
Cover the casserole dish and bake for 45 minutes to 1 hour or until potatoes are fork-tender.
Stir at least once halfway through to prevent mixture from sticking.