1. Heat oil in large saucepan over medium heat and cook celery, carrot, onion and thyme until vegetables are almost tender, about 3 minutes. Stir in 1 cup water and bring to a boil over high heat. Reduce heat to low and simmer until vegetables are tender, about 10 minutes.
2. Process vegetable mixture and broccoli in food processor or blender until smooth; return to saucepan.
3. Stir in remaining 1/2 cup water, broth and sauce. Cook, stirring occasionally, until heated through, about 10 minutes.