1. Preheat oven to 400 F. Spray a large (or 2 smaller ones) oven safe cooling rack with baking spray and set on top of a baking tray.
2. Cut washed, unpeeled sweet potatoes into fries about 3/4 cm x 3/4 cm (almost 3 inches, so must be length) or slightly larger shoestring size.
3. Soak in a large bowl of cold water for at least 10-20 minutes (longer is better). Remove to kitchen towels and pat dry or allow to air dry and then pat dry to make sure there is a very little moisture left.
4. In large deep bowl, whisk egg whites until very frothy, almost to soft peaks. Toss cut, dried fries into egg whites until fully coated. Add flour one TBS at a time to coat and then add spices. Be sure to fully coat and distribute the spices. You will have very coated fries at this point, which is fine. A thick coating means crispy fries!
5. Lay on greased rack in one layer, do not allow fries to touch or become crowded. Bake for 30-40 minutes or until lightly browned on ends and crispy. Begin checking fries after 30 minutes and continue to check every couple of minutes or so to ensure they do not burn. Serve with sriracha/mayo mix, i.e., Cock Mayo.