Preheat oven to 350°.
Brush the inside of the quartered and seeded squash with olive oil, season with salt and pepper and place on a roasting pan in the preheated oven. Roast until fork tender, approximately 45 minutes. Let cool, then peel and chop the meat into 1-inch pieces. Reserve.
Sauté the mushrooms in 2 tablespoons of the butter until they release their liquid and are cooked dry. Reserve.
Add the remaining 2 tablespoons of butter to a stockpot placed over medium heat and sweat the onions, garlic and ginger until they are soft. Do not allow them to brown. Add the curry powder and cook 1 minute to “bloom” the spice, then add the squash meat and the stock. Simmer 30 minutes, then remove from the heat and purée in a blender in small batches (be very careful when blending hot ingredients as it can splatter).
Season the purée with salt and white pepper to taste, then pass through a fine sieve or strainer. Stir in the mushrooms. The soup may be rewarmed and served right away, or cooled to room temperature, then placed in the refrigerator until ready to serve.
When ready to serve, heat the soup, then pour into preheated bowls, or into 1 large or individual hollowed-out squash shells. Garnish with a dollop of crème fraîche, a sprinkle of minced chives and small crispy croutons.
Yield: 8 servings