CAKE ICEBERG, shortbread dough with meringue!

Iceberg cakes 20-23 pcs
Shortcrust pastry:
100 gr. butter, room temperature
200 gr. wheat flour
80 gr. corn starch
40 gr sugar
1 egg
1 egg yolk
8 gr. vanilla sugar
1 tsp baking powder
a pinch of salt
150 gr. black currant jam (or other)
Meringue:
3 egg whites
150 gr. powdered sugar
1.5 tsp corn starch