Heat the butter in a pot on medium heat. Add the celery, peppers, and onions and cook them in the butter until they are a light brown.
Add the scallions, cheese, broccoli, onion powder, pepper, salt and water. Raise the heat to bring the pot to a boil. Once the boil is reached lower it down to simmer and let it cook for about half an hour. You will know it's ready when the vegetables start to soften up.
Put the whole soup in a blender and blend to your preference of texture.
Serve with the broccoli florets as a decoration on top.