9-inch round Cinnamon Roll Cake with Cinnamon Buttercream. Gumpaste Sunflower (my first). This was an experiment cake with the recipe and flower. The advantage/disadvantage of being a family member of a cake baker/artist, the family becomes part of the experiment. I made this cake for one of my son’s wife. Her favorite flower is the Sunflower and she loves cinnamon rolls. I didn’t want to make cinnamon rolls, so I experimented to make a cinnamon roll cake. It tasted very good. My son loved the icing. As far as the recipe for the cake goes, I will tweak it just a little bit. I thought of a few things I could have done after it was in the oven about five minutes.