Preheat oven to 500°F Spray large baking sheet with vegetable oil spray. Toss sweet potatoes with oil in large bowl. Sprinkle generously with salt and pepper. Spread sweet potatoes in single layer on prepared baking sheet. Bake until sweet potatoes are tender and golden brown, turning occasionally, about 30 minutes. Transfer sweet potatoes to platter.
Mix parsley, thyme and garlic in small bowl. Sprinkle over sweet potatoes.