Preheat the oven to 350 degrees and lightly spray a 9″x 13″ baking dish with nonstick spray. Open two packages of cinnamon rolls and place cinnamon rolls in the baking dish. Set the containers of frosting to the side. Pour heavy whipping cream into the bottom of the pan and in between the rolls. Melt butter and mix with brown sugar, cinnamon and vanilla. Pour the butter and sugar mixture over the rolls. Cover the baking dish with foil and bake for 35 minutes. Uncover and bake an additional 5-10 minutes to allow the rolls to brown. Let cinnamon rolls cool for 10-15 minutes before spreading with frosting.