In a large soup pot melt butter. Add chopped onions, saute,stirring occasionally,5-7 min. In a small bowl combine flour,salt,pepper,dried oregano and cayenne pepper. Remove pot/onions from heat,using a wooden spoon stir flour,spices and seasonings into butter and onions, making a smooth paste.Gradually stir in chicken stock, carefully to avoid lumps. Add fresh mushrooms and bay leaf, return to heat and bring to a boil,stirring constantly. Reduce heat,cover and simmer for 30 minutes. Add heavy cream,stirring constantly 2-3 minutes until heated through.
Remove bay leaf.
Crumble sausage,brown and drain.
Place desired amount of sausage in a bowl and ladle the soup over it. Enjoy!