Prepare the Oven and Baking Sheet: Preheat your oven to 450°F (230°C) for a perfect balance of crispy edges and tender centers. For even crispier fries, you can increase the temperature to 500°F (260°C). Place a heavy-duty baking sheet or roasting pan inside the oven while it preheats, allowing it to get hot. This will help the fries develop a nice caramelized crust once they hit the pan.
Peel and Slice the Sweet Potatoes: Peel the sweet potatoes and trim off the ends. Cut each sweet potato in half lengthwise, and then cut each half into wedges about ¼ to ½ inch thick. Alternatively, for uniform slices, you may use a mandoline to cut the sweet potatoes into thin rounds.
Season the Fries: Transfer the sweet potato wedges to a large mixing bowl. Drizzle the olive oil over the potatoes and sprinkle with kosher salt and your chosen spices. Use your hands or a spatula to toss everything thoroughly, ensuring each piece is evenly coated with oil and seasoning.
Arrange Fries on Hot Baking Sheet: Carefully remove the preheated baking sheet from the oven. Spread the sweet potato pieces out in a single layer on the hot pan. Avoid overcrowding so the fries roast evenly and become crisp rather than steaming.
Bake and Flip for Even Crispiness: Place the pan back in the oven and roast the fries for about 10 minutes. Then, using tongs, carefully turn each piece to promote even browning. Continue baking for another 5 to 15 minutes, depending on your oven temperature and fry thickness, until the fries are golden brown and crisp on the edges but tender inside.
Cool and Serve: Remove the fries from the oven and let them rest for about 5 minutes to allow the exterior to firm up slightly. Serve warm alongside your favorite dip or as a flavorful side dish.