Step 1: Prep Your Sweet Potatoes. Thoroughly scrub the sweet potatoes. You can peel them or leave the skin on for extra fiber and rustic appeal. Slice off the ends.
Step 2: The Art of the Uniform Cut. Slice each sweet potato lengthwise into 1/4-inch thick planks. Then, stack these planks and slice them again into uniform 1/4-inch thick fries. Consistency is key for even cooking.
Step 3: The Soaking Secret for Starch Removal. Place the cut sweet potato fries into a large bowl and cover them completely with cold water. Let them soak for at least 30 minutes, or up to an hour, to draw out excess starch.
Step 4: Dry, Dry, Dry! This Cannot Be Overstated. Drain the sweet potato fries thoroughly. Spread them out in a single layer on a clean kitchen towel or paper towels and pat them exceptionally dry. Any residual moisture will lead to steaming, not crisping.
Step 5: Perfect Seasoning & Starch Power Activation. Return the dried sweet potato fries to a large, clean bowl. Drizzle generously with oil and toss to coat. Then, sprinkle with cornstarch and toss again until evenly coated. Finally, add salt, black pepper, smoked paprika, garlic powder, and onion powder, and toss one last time until perfectly distributed.
Step 6: Preheat to Perfection & Intelligent Arrangement. Preheat your oven to 425°F (220°C). Line a large baking sheet (or two, if needed) with parchment paper. Arrange the seasoned sweet potato fries in a single layer, ensuring plenty of space between each fry to prevent steaming.
Step 7: The Strategic Bake & Flip. Bake for 15-20 minutes. Carefully remove the tray from the oven and flip each fry using a spatula or tongs. Return to the oven and bake for another 10-15 minutes, or until deeply golden brown and wonderfully crispy. Keep a close eye during the last few minutes to prevent burning.
Step 8: Serve Immediately & Enjoy. Transfer the crispy fries to a serving platter. A final sprinkle of flaky sea salt is a great touch. Serve hot with your favorite dipping sauce and enjoy your perfectly crispy oven baked sweet potato fries!