Preheat oven to 400 degrees.

In a large bowl, combine flour, sugar, and cinnamon. Stir with whisk.

In a medium sauce pan, add butter, water and shortening. Heat over medium heat until butter and shortening melt and bring to a boil.

After mixture reaches a boil, remove from heat and add it to the dry ingredients. Stir to combine.

Add buttermilk, baking soda, eggs, and vanilla in that order mixing between each addition.

Stir in apples.

Grease a 15X13 jelly roll or bar pan. Pour in mixture and spread evenly.

Bake at 400 Degrees for 20 minutes Let cool on wire rack for 10 to 15 minutes.

While cake cools, make the frosting. Combine the butter, caramel bits, and milk in a glass measuring cup. Heat in 30 second increments stiring and heating until the butter and caramel are all melted. Add in the powdered sugar and stir until smooth and well combined.

Pour frosting over warm cake and let cool completely before serving.

Cover and store at room temperature for up to 3 days.