Beat the eggs with the sugar and lemon zest. Fold in the flour then spread over a baking sheet. Bake at 375 degrees F for about 22 minutes. Cool and cut into cubes measuring 1 1/4 x 1 1/4".
Prepare the syrup by boiling 1/2 cup sugar with 1/2 cup water. Stir in the lemon juice and kirsch and soak the cake in the mixture.
Grate the lemon rinds. Squeeze the juice from one lemon. Bring the water to the boil. Mix the eggs with the sugar and the cornstarch. Add the lemon rinds, lemon juice and hot water and bring slowly to the boil, stirring all the time.
Place layers of soaked cake, berries and lemon cream in transparent serving bowls.