Prepare spinach, pour water in pot and then add spinach.
Cook spinach then strain out excess water and set aside.
Prepare Bechamel sauce, heat butter in medium sized pan.
As butter heats and foams (medium heat) slowly stir in your flour until it turns golden brown in color.
Slowly stir in heavy cream until you have a creamy thick white sauce.
Add your sour cream,onion powder, and salt. Then stir.
Now add your cheese. Stir.
Once cheese sauce is completely melted and homogenous, pour into your spinach and simmer for a few minutes.