Mix dry spices and sauté in dry pan till fragrant. (I did not use all this mix, but added till it tasted right) Roast butternut for an hour with butter and seasoning. Heat oil and cook onions. Add half spice mix and coat onions. Puree butternut. Add butternut, coconut milk, stock and remaining spices (to taste). Stir to combine and boil for several minutes. Turn down heat and cook for 40 minutes, covered. Garnish with sour cream, cilantro, coconut milk, as desired.