In a 2-quart microwave-safe bowl, combine water, carrot, fennel, bouillon, and rice. Cover and microwave on high for 5 minutes. Stir tomatoes and onion into carrot mixture; cover and microwave on high 6 minutes. Add garlic, stir well, cover, and microwave on high 5 to 6 minutes longer or until rice is very tender. Stir in butter, if desired, and add salt and pepper. Set aside for 10 minutes. In batches, puree soup mixture in blender until very smooth. Serve.