Brush the sides and flesh of squash with olive oil. Arrange squash halves, cut side down, on a baking sheet lined with parchment paper. Bake in preheated oven until slightly tender, about 25-30 minutes. Remove from oven. Carefully, turn squash halves flesh side up.
In a small bowl combine brown sugar, and cinnamon. Evenly divide butter among squash halves. Sprinkle with brown sugar mixture, salt and pepper.
Return to oven. Bake at 400°F until squash is easily pierced with a fork, about 20 minutes, or until tender. Serve warm.
Notes
Tiffy's Tips~To make acorn or butternut squash easier to cut in half, microwave the entire squash for 1 to 2 minutes on HIGH. This will soften the squash for slicing. After microwaving, cut the squash in half lengthwise; remove and discard seeds with a fork or spoon.