Preheat oven to 400F. Line 2 large baking sheets with parchment paper and set aside.
Peel the sweet potatoes and use a mandolin slicer to cut the sweet potatoes into paper-thin rounds. (I set mine to the thinnest setting).
Combine olive oil,salt, black pepper, and dried rosemary in a large mixing bowl. Add sliced sweet potatoes to the bowl and toss to coat.
Spread sweet potato slices into a single layer on the baking sheets, and leave space around them.Bake about 10-12 minutes on each side turning them once, until golden. Remove from the oven and cool the sweet potato chips on cooling racks for about 5-10 minutes. They will crisp up a little more as they cool.
