Cook frozen artichoke hearts in salted water according to package instructions.
Allow to cool in their cooking liquid and puree in blender with 1 or 2 cups
of their cooking broth. Set aside.
In a Dutch oven, heat butter and add flour. Cook, stirring often, for 2
minutes, but do not let it brown. Slowly add 2 cups of the broth and the evaporated
milk or cream. Cook until smooth, stirring often. Add remaining broth, then
season to taste.
Strain pureed artichokes into chicken stock mixture and bring to a boil.
Lower heat and simmer for 5 minutes, stirring often. Add nutmeg and correct
Serve laced with dry sherry and topped with fresh garlic croutons.