This unusual cake batter may be made in other flavors by changing the liqueur. Though not a layer cake, I include it here because it is a rich dessert cake.
Set a rack at the middle level of the oven and preheat to 300 degrees.
For the cake batter, cut the chocolate finely and set it aside. Combine the sugar and water in a saucepan and bring to a boil over low heat, stirring occasionally to make sure all t