Place oven racks in the middle two levels, right next to each other. Preheat oven to 225°F.
Wash and dry the sweet potatoes, but don't remove the skin.
Thinly slice potatoes with a mandoline slicer (setting of 2) or sharp knife so they are about ⅛ to 1/16 inch thick.
Place slices in a single layer on sheet pans lined with parchment paper or foil and coated with cooking spray. Use a pastry brush to lightly brush the slices with olive oil. Lightly season with sea salt.
Bake for about 1 ½ hours, flipping the slices at the 1-hour mark and rotating the pans. Check for doneness every 15 minutes after that.
Cook until sweet potato chips are crisp, not burnt, and lightly curled at the edges. They will continue to crisp as they cool.
Notes
See step-by-step pictures, serving ideas, and more above!Note: The cooking time will differ depending on the thickness of the sweet potato slice, the individual oven, and the amount of oil brushed on the sweet potato slice.Top tip: Slice the sweet potato into thin slices with a uniform thickness so they cook evenly. Use a mandoline slicer if you have one! Storage: Store leftover sweet potato chips in an airtight container for several days. They may soften. If they do become soft, revive them by baking them in the oven at a low temperature (around 225°F) for a few minutes until they crisp up again. You can also use the air fryer.