Preheat your oven to 350°F (175°C) and prepare a 9x13 baking pan by lining it with parchment paper.

Whisk together flour, baking powder, salt, and ground cinnamon in a medium mixing bowl.

In a large mixing bowl, combine vegetable oil, granulated sugar, and brown sugar until smooth and creamy. Beat in eggs one at a time, and then add vanilla extract.

Gradually add the flour mixture to the wet ingredients, stirring gently until just combined. Fold in chopped apples.

Pour the batter into the prepared pan and bake for 30 to 35 minutes, or until a toothpick comes out clean.

Let the cake cool completely in the pan for at least 30 minutes.

In a mixing bowl, beat together cream cheese and butter until smooth. Mix in vanilla extract and ground cinnamon.

Gradually add powdered sugar to the cream cheese mixture, adjusting with half-and-half if necessary for desired consistency.

Once cooled, spread the frosting generously over the top of the cake.

Slice into squares and serve.