Preheat the oven to 250°F.

In a large bowl, toss the sweet potato slices with the olive oil.

Pour them out onto one or two large baking sheets in a single layer, and season with salt and pepper.

Bake for 1½ to 2 hours, checking on them after 30 minutes. At the halfway point, check them again to prevent burning, and flip them.

Serve warm or at room temperature.