Cut squash in half, scoop out seeds and loose pulp. Rinse and prick the insides several times with a fork.
Place face down in a glass baking dish and add about an inch of water. Bake at 350° for 30 minutes.
Remove fom oven, drain water and turn squash halves over. Add 2-3 tablespoons of maple syrup and 1 tablespoon of butter to each.
Use a spoon to drizzle syrup and butter so that the inside of the squash is well coated.
Bake for another 30 minutes (or till very tender when pricked with a fork), drizzling syrup over insides every 10 minutes.
Serve in the shell.
TIP: you may need to cut a little off the tip of the squash or remove the stem from the top so that it will sit flat. Be careful not to remove too much, otherwise the filling will leak out while baking.
NOTE: Buttercup squash also works well in this recipe! Cut in half and follow the same baking instructions as for acorn squash. The shells aren't as firm after baking as acorn squash, so scoop out the squash and mash til smooth.