Preheat your oven to 400°F (200°C). Use a sharp vegetable peeler to remove the tough outer skin of the butternut squash until you reach the bright orange flesh. Slice off the top and bottom ends of the squash to create stable surfaces.
Cut the squash in half lengthwise and scoop out the seeds and pulp with a spoon. Slice the squash into even 1-inch cubes. Keeping the sizes consistent ensures that every piece cooks at the same rate and finishes at the same time.
Place the squash cubes directly on a large rimmed baking sheet. Drizzle with olive oil and maple syrup if you prefer a sweeter finish. Sprinkle with salt, pepper, and garlic powder. Toss everything together with your hands or a spatula until every cube is well-coated.
Spread the squash in a single layer, making sure the pieces are not crowded. Roast for 25 to 30 minutes. Halfway through the cooking time, use a spatula to flip the cubes so they brown evenly on all sides.
Remove the tray from the oven once the squash is fork-tender and the edges are golden brown. Sprinkle with fresh thyme or rosemary while the squash is still hot and serve immediately.