1. Bring all ingredients to a boil in a Dutch oven over medium-high heat; reduce heat to low, and simmer, stirring occasionally, 50 to 60 minutes or until carrots are tender. Remove from heat, and cool 15 minutes.
2. Remove thyme sprigs. Process soup, in batches, in a blender or food processor until smooth. (For a thinner soup, stir in more broth, 1 Tbsp. at a time.) Spoon into individual bowls, and serve immediately.