With a high speed blender, blend in small batches until completely smooth. Add raw spinach at this point when you are blending. I have a Vitamix and love it. I think I use it 2-3 times a week. A regular blender will probably also work, but may take a little longer. To thin to the consistency you want, you can add more chicken broth. I use cashew milk, which has a very smooth consistency like cream and has only 25 calories per 8 ounces. It is loaded with calcium and makes the soup taste as if it had cream as a main ingredient.