Preheat oven to 350°F (180°C).

Combine chocolate, margarine, half the sugar, and water in a saucepan and cook over low heat until the sugar is dissolved and the chocolate melted. Cool thoroughly.

Beat the eggs and the remaining sugar together. Add liqueur and mix well. Stir in flour, baking powder, and chocolate mixture.

Pour into a greased 9- x 13-inch (23- x 33-centimeter) baking pan and bake for 30 minutes, or until set.

Combine eggs, sugar, and lemon juice in a saucepan and cook while stirring, until the mixture thickens. Remove from flame and add margarine. Stir until margarine melts. In a small bowl, combine cornstarch and water. Add to margarine as it cools. Allow to cool completely.

Strain the cherries, puree in a food processor, and add to the mixture.

Beat the parve whipping cream until stiff. Carefully fold in the cherry mixture and spread over the cake. Freeze.

Before serving, slice into 2- x 3/4-inch fingers. Store in the refrigerator or freezer.