Using a mandoline (or knife- but be careful!), thinly slice the beets into even, circular pieces.
Place beet slices in a large bowl, and drizzle with olive oil. Mix to coat.
Place beets on 3 baking sheets without overlapping. Sprinkle with garlic powder, sea salt, and black pepper. Bake for 25 to 30 minutes or until crispy (but not burnt- happened to me the first time)! Keep a careful eye on them!