Preheat the oven to 400 degrees and grease an 8-9 inch cast iron skillet, pie plate, or square pan with butter.

Cut the cinnamon rolls into bite sized pieces, and add them to the pan. Stir in the apples, then drizzle with butter, cinnamon, and 2 Tablespoons of the brown sugar. Stir to combine and spread evenly over the pan.

Sprinkle the final Tablespoon of brown sugar on top.

Place in the oven and bake for 14-17 minutes or until cinnamon rolls are puffed and golden.

Meanwhile, make the frosting: Use a hand mixer to beat together the cream cheese and butter until well combined. Add the powdered sugar and beat on low speed until combined, then on high until the mixture is light and fluffy. Stir in the vanilla. Slowly incorporate the milk, a Tablespoon at a time, until the mixture reaches the desired consistency. I prefer it be thick, but pourable. Pour over the warm casserole and serve!