Heat butter and oil in a Dutch oven over medium heat until the butter melts. Add onion and celery; cook, stirring occasionally, until softened, 4 to 6 minutes. Add garlic parsley; cook, stirring, until fragrant, about 10 seconds.
Stir in broccoli, add water and broth; bring to a lively simmer over high heat. Reduce heat to maintain a lively simmer and cook until very tender, about 8 minutes.
Puree the soup in batches in a blender until smooth (Use caution when pureeing hot liquids.) salt and pepper
Ladle the soup evenly among serving bowls. Serve immediately with garlic herb Toast or parmesan Toast.