Preheat oven to 350
Spray a 9x9 baking dish with cooking spray and arrange cinnamon rolls in dish
Pour heavy cream on bottom of baking dish
Mix together butter, brown sugar, and cinnamon and top rolls/heavy cream with butter mixture
Bake for 30 minutes
While baking, mix together the packet of icing that comes with the cinnamon rolls, softened butter, vanilla, and powdered sugar. Then add a splash of milk (plus more if needed) to thin out
Once cinnamon rolls have finished baking, remove from oven and top with icing. Serve immediately.