Mix ricotta, 1 pint of whipped heavy cream, sugar, and vanilla in a bowl till smooth. Add one roughly chopped chocolate bar. Fold in.
Spray a large bowl with nonstick cooking spray (like Pam). Slice sponge cake into half-inch pieces. Line the bowl with one layer of cake. Follow with a layer of filling, making sure to come up to top of bowl. Continue alternating layers of cake and filling till you have reached the top of bowl. Finish with a layer of cake. Seal with plastic wrap and refrigerate overnight.
Remove plastic wrap. Place a pretty cake dish on top of bowl. Invert the cake and remove bowl. Frost with remaining pint of whipped heavy cream. Decorate with 2nd chocolate bar curls and drained maraschino cherries.
My mother-in-law, Lucille Priore Crosby, makes this fabulous cake every Christmas season. The filling is like a cannoli filling but this is so much better because of the light sponge cake and the cool whipped cream.