Preheat oven to 375 degrees

Place the butter in a cast iron skillet on top of the stove. Add the onion to the pan. Saute on low just until the onion has softened, add the garlic, cook and stir 1 more minute. Add the potatoes, toss to coat well with the butter mixture. Place the cast iron skillet with the potatoes in the preheated oven. Bake at 375 degrees for 45 minutes (turning the potatoes with a spatula once halfway through baking) or until golden brown and softened. Season with salt and pepper, sprinkle with chopped parsley.

If using a baking dish - melt the butter in a saute pan, add the onion to the butter. Saute until onion is softened, add the garlic, stir and cook 1 more minute. Add the potatoes to the saute pan, toss to coat. Place the potatoes into a baking dish, place the baking dish into the oven, bake at 375 degrees for 45 minutes ( turning potatoes once with a spatula halfway through baking) or until golden brown and soft. Season with salt and pepper, sprinkle with chopped parsley.