Cut each squash in half lengthwise. Scoop out and discard seeds. Place squash halves, cut side up, in a shallow roasting pan. Place one-fourth of the maple syrup and 1 teaspoon margarine or butter in the cavity of each squash half. Arrange garlic, carrot, and onion around squash. Pour 2 cups of the chicken broth in pan; cover tightly with aluminum foil. Bake in a 350 degree F oven for 2 hours or until vegetables are very tender.
Remove pan from oven; let vegetables cool slightly. Scoop pulp from squash shells and stir into vegetable mixture.
Place half of the squash mixture in a blender container or food processor bowl. Cover and blend or process until smooth. Repeat with remaining squash mixture. Transfer entire squash mixture to a large saucepan; stir in remaining chicken broth. Heat and stir until mixture boils. Stir in whipping cream. Do not boil. Season to taste with salt and pepper. If desired, garnish each serving with basil or parsley. Makes 6 servings.