Split the squash lengthwise and bake face-down in a 375 degree oven on an oiled tray, 30 minutes or until soft. Cool and scoop out the insides. You’ll need about 3 cups worth. Put it in the blender with the water or stock and puree until smooth. Combine in a kettle or saucepan with the orange juice.
Heat the butter in a skillet and add the garlic, onion, salt and spices. Sauté until the onion is very soft. (You may need to add a little water if it sticks.) Add mushrooms, cover, and cook 10 minutes. Add the sautéed ingredients to the squash, scraping the skillet well. Heat everything together very gently. Taste to correct seasoning; you may want more cayenne or salt. This is a fairly sweet soup, so you may want to spruce it up with some fresh-squeezed lemon juice. Serve topped with yogurt and almonds.
This soup need not be served immediately. It can simmer a while and the flavors will mature.