Preheat oven to 425. Set a wire rack on top of a baking sheet. Spray rack with non-stick spray.
Grate sweet potatoes and squeeze all the moisture. The more water you remove, the crispier the potatoes.
Combine sweet potatoes, egg whites, salt, cinnamon sugar, and butter in a large bowl and mix until combined.
Scoop out potato mixture with spoon, form into small patty shape, and set on wire rack. Try and press as thin as possible. Repeat until potatoes are all on the wire rack.
Bake for 20-30 minutes, or until potatoes and dark around the edges and crispy.
Recipe by In The Kitchen With KP at https://www.inthekitchenwithkp.com/recipes/sweet-potato-crisps