Preheat oven to 400 degrees F. Scrub potatoes, or peel if desired.
Cut potatoes in half lengthwise, and then lengthwise again. If the pieces are too big, cut them once more.
Put the potato slices in a bowl. Drizzle with olive oil. Sprinkle with salt and pepper, and a liberal amount of oregano.
Spread out in a single layer on baking sheet. Bake in preheated oven about 30 minutes, turning potatoes occasionally so that all sides brown. In last few minutes, dot potatoes with some butter and finish baking.