What's for dinner? Easy Broccoli Cheese soup!

I have been making this soup for over 10 years.  I got this recipe from an old friend, Diane.
Enjoy!

Broccoli Cheese soup

1 onion-diced
2 stalks celery-chopped
4 T butter
4 T flour
2 bunches broccoli-cut up and steamed
1/2 t pepper
1/2 t dry mustard
2 c milk
2 c chicken broth
2 c velveeta shreds

Cook broccoli until tender
Melt butter in soup pot and add celery and onion.  Cook til tender.
Stir in flour, pepper and dry mustard.
Add milk and broth.  Heat to boiling.  Stir so it doesn't stick.
Add velveeta.  Stir constantly til melted and creamy.
Stir in cooked broccoli