This decadently rich soup was created by our Organic Kitchen at our Farm Stand in Carmel Valley, CA, for the holiday season.
Position a rack in the lower third of the oven and preheat to 350 degrees F.
Cut the squash lengthwise and remove seeds and strings. Brush the cut surfaces with the oil or melted butter. Season with salt and pepper. Place squash, skin side up, in a shallow pan, and pour 1/2 inch of water into pan. Transfer to the oven and roast for 45 minutes, or until the flesh is pliable when you poke the skin with your finger. Set aside and let cool. When cool, scoop out the flesh with a large spoon.
In a large, heavy-bottomed pot, melt the 3 tablespoons of butter and add the onions, shallots, garlic, and thyme. Cook over medium heat until the onion is translucent.
Add the squash and stock. Bring to a boil, reduce heat to low, and simmer for 30 minutes.
In a separate bowl, mix together the 1/2 cup softened butter and flour to make a paste (this is called beurre manie).
Puree the squash in a blender or food processor. Return to a saucepan and whisk in some of the butter-flour paste. Simmer over low heat until the mixture thickens. Add more beurre manie as needed.
Just before serving add the brown sugar, cream and truffle oil. Season to taste and serve hot.