Position racks in the upper and lower thirds of your oven. Preheat oven to 400 degrees F. Line 2 baking sheets with parchment paper.
Place the egg white in the bottom of a large mixing bowl. Briskly whisk until it is foamy.
Cut sweet potatoes into fry-shaped sticks that are about ¼- to ½-inch wide and 3-inches long. Make the pieces as uniform as possible so that the fries bake evenly. Place the fries in the bowl with the egg white as you go.
Drizzle the fries with the olive oil.
In a small bowl, stir together the curry powder, kosher salt, ground black pepper, garlic powder, and cayenne pepper.
Sprinkle the spices over the fries. Toss to coat the fries evenly. Try to get them to be as evenly moistened and seasoned as possible.
Spread the fries onto the baking sheets, dividing them evenly between each. Make sure the fries are not crowded, or they will steam and not crisp up.
Bake the sweet potato fries for 20 minutes.
Remove the pans from the oven, then flip the fries over (I recommend using a large spatula—scoop the fries in big sections, then use a fast turn of your wrist).
Rearrange the fries back into a single layer to make sure they are not overlapping. If any look like they are browning too quickly, keep these towards the center or front of the baking sheet (the back of the oven tends to be the hottest).
Return the pans to the oven, switching their positions on the upper and lower racks.
Continue baking until the fries are crisp and brown on the outside and tender on the inside. The ends may look very dark on some of the fries, and you’ll see lighter brown spots in a few places. This will take about 10 to 15 additional minutes, depending on your oven and what size you cut the fries.
Remove from the oven. Sprinkle with a pinch of additional salt. Serve immediately.
