Pre-heat oven to 450 degrees and spray baking sheet with non-stick cooking spray. (I also like to use parchment paper on a baking sheet if I have it. It allows all the cheese to get crispy and slides off easy, which makes clean up a cinch!)
Wash sweet potato and dry VERY thoroughly (if you don’t dry properly, you will have soggy fries). You could also peel the sweet potato here… but the skin is the healthiest part!
Cut the sweet potato in half lengthwise and place both halfs flat side down on cutting board so it won’t go rolling around on you. Cut a thin slice from both ends (the ends tend to cook quicker than the rest of the potato and get burnt).
Take a half of the sweet potato and cut it into large slices about 3/4 inch thick. You’ll then cut the larger slices into fries. Your fries should be 1/2 inch to 3/4 inch thick. Then repeat this on other half!
Place cut potatoes on baking sheet and spray with non-stick cooking spray. Add salt, pepper and grated Parmesan (and/or whatever other seasoning you choose) and toss everything together to coat potatoes evenly.
Spread potatoes out evenly on baking sheet and brush with egg white. Bake for 15 minutes (try not to open the oven during this time). Then take them out, flip them over with tongs, brush the other side of the fries with egg white, and bake for another 10 minutes (this allows both sides to get crispy and browned! If you like yours a little less brown you can reduce the cooking time by a few minutes on each side).