Preheat the oven to 400°F (204°C). Line a large baking sheet with parchment paper for easy cleanup.
Prepare the vegetables: Peel and chop the sweet potatoes and carrots into evenly sized chunks (about 1-inch).
Season: In a large mixing bowl, combine sweet potatoes and carrots. Drizzle with olive oil and sprinkle with salt, pepper, garlic powder, and thyme. Toss until well coated.
Arrange on baking sheet: Spread vegetables in a single layer on the prepared baking sheet. Ensure pieces are not overlapping or crowded.
Roast for 30–40 minutes, flipping halfway through. Check for doneness around the 30-minute mark—vegetables should be golden and fork-tender.
Optional finishing touches: Drizzle with maple syrup, balsamic vinegar, or sprinkle with fresh rosemary just before serving.
Serve warm with your favorite main dish or enjoy as a standalone veggie side.