Place the ricotta into a fine mesh sieve and nestle this over a bowl, place into the refrigerator overnight to allow the excess moisture to drain out before proceeding with the cassata recipe.
Place the ricotta into the bowl of a mixer and beat with the paddle attachment until the curds smooth out. Mix the drained and beaten ricotta with 1 cup powdered sugar, vanilla extract, cinnamon, chocolate chips and half the candied fruit. Set aside.
Lightly oil a 10-inch springform pan with canola oil. Slice the sponge cake very thinly so that the springform may be lined with it in an even layer. Line the sides and bottom of the pan with the sponge cake. Pour the ricotta filling into the cake-lined pan. Place a final layer of cake over the ricotta filling; this now creates the bottom to the cassata. Before serving, the cassata will be inverted onto this cake bottom. Refrigerate the cassata overnight to firm the filling.
Invert the springform pan on a wide platter. Open the hinge and remove the springform sides and bottom.
The cassata may now be finished by either covering with a heavy coating of the remaining powdered sugar or may be coated with a thin layer of green marzipan. Either way, the remaining candied fruits should be used to decorate the finished cassata. Slice thinly and serve.