Instructions
1. Preheat the oven to 350 degree F. Lightly grease and flour a 9-inch square cake pan.
2. Mix together the egg, oil, and sugar until the sugar is fully incorporated. Stir in the canned tomato soup.
3. Add in the flour, baking soda, salt, spices, and orange zest to the wet ingredients and beat until smooth. Fold in the raisins and nuts until evenly distributed.
4. Pour the batter into the prepared cake pan. Bake for 35 to 40 minutes, or until the edges begin to pull away from the pan and a toothpick or cake tester inserted into the center comes out clean. Remove the cake from the oven and allow it to cool completely on a rack.
5. While the cake cools, combine the softened cream cheese, confectioners' sugar, orange zest, and butter (if using) in a large mixing bowl and beat until smooth and fluffy. Spread over the cooled cake and serve.