Preheat oven to 400 degrees F (200 degrees C). To make the croutons, combine softened butter, brown sugar, and cinnamon. Spread butter mixture evenly over one side of each bread slice. Place bread, buttered side up, on a baking sheet. Bake 8 to 10 minutes, or until bread is crisp and topping is bubbly. Cut each slice of bread into 8 small triangles or squares.
Saute onion in butter in a medium saucepan until tender. Add 1 can chicken broth; stir well. Bring to a boil; cover, reduce heat, and simmer 15 minutes.
Transfer broth mixture into the container of a blender or processor. Process until smooth.
Return mixture to saucepan. Add remaining can of broth, pumpkin, salt, ground cinnamon, ground ginger, and ground pepper; stir well. Bring to a boil; cover, reduce heat, and simmer 10 minutes more, stirring occasionally.
Stir in whipping cream and heat through. Do not boil. Ladle into individual soup bowls. Top each serving with Cinnamon Croutons.
