Steam Broccoli.Set aside. (I like to use fresh broccoli.) In a Stockpot or dutch oven,melt butter,add onion. Reduce Heat.Stir. Add broccoli and Chicken Broth.Increase heat to Med/Low. Add in cheese. stir until all cheese is melted.
In a small pyrex mix water and cornstarch until dislved.Add to pot and stir until thickened.
Using an immersion blender, blend in pot until smooth and creamy