Preheat your oven to 350°F (175°C). This ensures that your cake bakes evenly.
Grease and flour your 9x5 inch loaf pan. This will prevent your cake from sticking.
In a large mixing bowl, combine the room temperature butter and vegetable shortening. Using an electric mixer, beat them together until the mixture is light and fluffy.
Gradually add in the sugar, continuing to beat the mixture. You want it to be well combined and creamy.
Add the eggs one at a time, mixing well after each addition. This helps to ensure that they are fully incorporated.
In a separate bowl, whisk together the all-purpose flour, salt, and whipped topping mix. Gradually add this to the wet mixture, alternating with the Fanta soda. Start and end with the flour mixture to ensure a smooth batter.
Mix in the vanilla extract and orange zest. If using, add a few drops of orange food coloring until you achieve your desired hue.
Pour the batter into your prepared pan and smooth the top. Bake in the preheated oven for about 60-70 minutes, or until a toothpick inserted in the center comes out clean.
Once baked, remove the cake from the oven and let it cool in the pan for 15 minutes. Then, transfer it to a cooling rack to cool completely.
While the cake is cooling, make the frosting. In a mixing bowl, beat together the softened cream cheese and butter until smooth. Gradually add in the confectioners sugar and mix until well combined. Finally, stir in the fresh orange juice and milk until you reach a spreadable consistency.
Once the cake is completely cool, spread the frosting generously over the top. If desired, you can garnish with additional orange zest for a pop of color.
