Cut off tips of asparagus and put them aside. Trim the stalks and cut into small pieces. Wash and pick the spinach. Bring the stock to a boil. Add the spinach and asparagus (but not the tips), cook until tender. Remove the vegetables, but save the stock. Run the solids through a food processor, with a little of the stock. (I find that my magic bullet is big enough) Have a small sauce pan of salted water boiling. Put in the tips and cook for about 10 to 15 min. Melt butter in a sauce pan, add flour, milk and stir until boils. Add the stock, the pureed asparagus and spinach. salt and pepper. Simmer for about 10 min. Place asparagus tips in a tureen add the cream and then add soup. serve as soon as possible.