Preheat the oven to 350°F. Line two standard muffin pans with grease-proof paper liners. Set aside.
In a large mixing bowl, add the packet of spice cake mix, whole milk, canola oil, eggs, and vanilla extract. Beat on medium speed using a handheld mixer for 2 minutes.
Fold the shredded Gala apple into the cupcake batter until all the shredded apples are evenly distributed.
Divide the batter evenly between the muffin cups. Bake for 17-19 minutes or until a toothpick inserted comes out clean.
Allow the apple cupcakes to cool in the pan for 5 minutes before transferring them to a cooling rack on the counter to cool completely.
While your cupcakes are baking, you can make your spiced cream cheese frosting by beating together on medium-high speed with a handheld mixer, the softened cream cheese, and unsalted butter. Beat for 1 to 2 minutes or until smooth and fluffy.
Add the vanilla extract, cinnamon, and salt to the cream cheese mixture. Mix until incorporated.
Add the sifted powdered sugar, one cup at a time, to the cream cheese mixture and beat until fully incorporated.
Lastly, add the heavy cream to the spiced cream cheese mixture and beat on medium-high speed for 1 to 2 minutes or until the frosting is smooth and thick.
Transfer the spiced cream cheese frosting to a large piping bag fitted with a decorative piping tip, and store in the refrigerator to firm up until you are ready to frost your cupcakes. The frosting needs a minimum of 30 to 45 minutes in the refrigerator to be firm enough to hold its shape when piped.
Pipe the frosting onto the cupcakes.
Garnish the frosted cupcakes with a drizzle of caramel sauce and a thin slice of Gala apple.