Cut squash in half and scoup out seeds. Place in baking pan with cut sides up. Melt 1/2 stick butter and pour into the whole where the seeds were. Place a tbsp of brown sugar in each hole. Season both halves with salt, white pepper, ginger, cinnamon and cloves. Pour about an inch of water in pan. About half way up the squash. Cover with foil and roast in 375 degree oven for 2 hours. Remove from oven and let cool a bit. Scoup out the squash and place in large Dutch oven.
Add the remaining ingredients and bring to a boil. Reduce to a simmer and simmer for 30 to 45 minutes. Taste and adjust seasonings.
Puree in batches with an immersion blender or food processor