Clean asparagus by trimming lower stems and removing ‘woody’ bottom portion. Slice asparagus into desired size then set aside. Melt butter in heavy sauce pan. Add onion and saute until onions are translucent. Add asparagus to pan and lower heat. Cook until asparagus is tender. Sprinkle onion and asparagus with flour and stir to coat evenly. Let this mixture cook slowly for about 1 minute while being careful not to burn flour. Slowly add chicken stock while stirring. Once stock is incorporated, add cream. Lightly simmer for about 30 minutes while stirring occasionally so not to let the soup stick to bottom of pan.
Serves about 8