1. Adjust the oven racks to the upper-middle and lower-middle positions and heat the oven to 400 degrees. Place 1/2 teaspoon of the oil on each of two rimmed baking sheets. Use a paper towel to spread the oil evenly over the entire surface and place both sheets in the oven.

2. Cut each sweet potato from end to end in eight thick wedges. Toss the sweet potatoes and the remaining tablespoon of oil in a large bowl to coat. Season generously with salt and pepper and toss again to blend. Carefully remove one baking sheet from the oven and place half of the sweet potatoes on the baking sheet cut-side down. Spread them out so that they do not touch each other. Return the baking sheet to the oven and repeat the process using the second baking sheet and the remaining sweet potatoes.

3. Bake until the cut side of the sweet potatoes touching the baking sheet is crusty and golden brown, 15 to 20 minutes. Remove each baking sheet from the oven and carefully turn the sweet potatoes, using a thin metal spatula. Bake until the second cut side of the sweet potatoes now touching the pan is crusty and golden brown, 10 to 15 minutes. Use the metal spatula to transfer the sweet potatoes to a platter and serve the oven-fried potatoes immediately.