Heat oil in a large saucepan over medium heat. Add celery, onion and carrot and stir to coat. Cover, reduce heat to medium-low and cook, stirring frequently, until soft, 8 to 10 minutes. Stir in the squash flesh, cumin, chipotle to taste and cloves. Add broth and simmer, covered, until the vegetables are very tender, 20 to 25 minutes.