Preheat oven to 350 degrees F (175 degrees C). Grease and flour one 13x9 inch pan.
Combine the creamed corn with the white sugar and 1/2 cup of the dark brown sugar. Stir in the eggs and the oil.
Combine the baking powder, flour, baking soda, salt and ground cinnamon. Add the nuts and raisins.
Add the flour mixture to the corn mixture and stir until just combined. Pour batter into the prepared pan.
Bake at 350 degrees F (175 degrees C) for 30 to 35 minutes. Let cake cool completely then frost.
To Make Frosting: Bring the butter and 1/2 cup dark brown sugar to a boil. Remove from the heat. Add the heavy cream and the confectioners' sugar. Mix until of frosting consistency. Add more confectioners' sugar if necessary. Use to frost cooled cake.
