One of the joys of spring is finding fresh rhubarb at the market. These rosy-red stalks are mouth-puckering tart, but when cooked with sugar they become an explosion of sweet-tart flavor in your mouth. This recipe combines a nutmeg flavored cornmeal cake with fresh rhubarb baked in a cast-iron pan. After baking the whole thing is flipped upside-down to show off the glistening pink rhubarb. Cut in slices and serve with sweetened whipped cream along with some Strawberry-Rhubarb Sauce.