Break the chocolate into pieces and melt. In a bowl, pour the air rice, pour the melted chocolate and mix thoroughly.Cover the bottom of the cake pan with plastic wrap to make it easier to get the cake. Put the chocolate-rice mixture there, flatten with a spoon, pressing well. Put in refrigerator for 40 minutes.In a saucepan, combine sugar, starch, cinnamon and water. Put on a slow fire and, stirring, cook until the sugar is completely dissolved. Add the cherries and continue to cook, stirring, until the mixture thickens like jam. Then remove from the heat and allow to cool to room temperature.Put the mixture of cherries on top of the air rice, spread evenly with a spoon. Put it in the refrigerator for an hour. You can serve the finished cake with powdered sugar or whipped cream.