Place the squash, cut side down, on a baking sheet and bake for 45 minutes to 1 hour, until the squash is easily pierced with a fork.
Scoop the flesh into a bowl and mash with a potato masher or a fork until fairly smooth.
Season to taste with salt and pepper.
Keep warm.
Combine the butter and maple syrup in a small saucepan and cook, stirring, over low heat until the butter is melted and blended with the syrup, about 2 minutes.