Cut squash in half lengthwise; discard seeds. Place squash, cut side down, in a 15x10x1-in. baking pan coated with cooking spray. Bake, uncovered, at 400° for 45-60 minutes or until tender. Cool slightly. Scoop out pulp; set aside., In a Dutch oven, cook onion and apple in oil until tender. Add garlic; cook 1 minute longer. Stir in the seasonings; cook until fragrant, about 10 seconds. Add broth and squash; bring to a boil. Reduce heat; simmer, uncovered, for 15-20 minutes to allow flavors to blend. Cool slightly. In a blender, cover and process soup in batches until smooth. , Return pureed mixture to pan; stir in sausage and carrots. Bring to a boil. Reduce heat; cover and simmer for 15-20 minutes or until carrots are tender. , Just before serving, stir in 2/3 cup yogurt, sage and vinegar. Serve with croutons and additional yogurt if desired.