Pre heat the oven to 400 degrees. On a large cutting board with a heavy knife, cut the squash in half. Remove the fiber and seeds (set seeds aside to roast for a snack). Brush the cut side of the squash with the olive oil. Place the cut side down on a rimmed baking sheet lined with parchment paper. Roast for 30 minutes or until the skin of the squash can be easily pierced with a fork and is soft all the way through.
Reduce the oven temp to 350 degrees. Butter a 9" x 13" casserole or a 2 qt dish well. Set aside.
Let the squash cool slightly until you can handle it with your hands. Peel the skin off the squash- it should come right off. Place the squash into a large bowl and mash slightly.
Add the roasted squash, melted butter, light brown sugar, salt, nutmeg, ginger, cinnamon, eggs, heavy cream, maple syrup and vanilla. Mash and mix all together until the squash and ingredients are well incorporated. Place the mixture into the prepared baking dish. Bake at 350 degrees fro 30 minutes.