Set a wire rack at the middle level of the oven and preheat to 350 degrees.
Grease a 9 inch springform pan with butter. Sprinkle on fine corn meal to just coat the butter. Sprinkling some in on the bottom of the pan and then patting and turning the pan will work well for this.
In a mixing bowl, combine the ricotta and sugar and stir with a rubber spatula to mix. Mix in the eggs, one at a time.
Mix in the vanilla and half of the cinnamon.
Fold in the chocolate chips until well distributed.
Pour the mixture into the pan.
Bake for 1 hour until well risen, golden on top and the custard is set. (doesn't jiggle) Watch carefully. Depending on your oven, the custard could be done in 50 minutes to 1 hour.
Chill the custard for several hours or overnight.
Unbuckle the ring and remove it. Use a long spatula to remove from the springform pan and slide it onto a platter.
Sprinkle with the remaining cinnamon. Dust lightly with confectioner's sugar before serving. Or top with a chocolate or raspberry sauce.