Cut the acorn squash into quarters and remove the seeds from the center of each quarter. Cut each quarter piece of squash into 1/4-inch thick slices.
To a mixing bowl, add the acorn squash slices, olive oil, thyme, salt, pepper, and garlic powder. Gently toss to coat the squash.
Spread the squash slices on a rimmed baking sheet in an even layer. Try not to overlap any pieces.
Roast the squash until golden brown and tender, about 20-25 minutes. Adjust cooking time as needed, I always check to see if the squash is done starting around the 15 minute mark.