Heat one tablespoon shortening, blend in flour and brown. Add onion and tomatoes and boil until mixture is reduced to about one-half. Add a pinch of salt and pepper and add to stock. Simmer ten minutes. Place mashed avocados in a soup tureen, add cream and mix well. Add a few drops of green coloring and stock. Stir and serve immediately with tortilla croutons which have been made by cutting tortillas into small squares and frying in three tablespoons shortening until golden brown. Bread cubes may be used instead. Yield: Six servings