Knead the flour, baking powder, sugar, egg and butter together to form a smooth dough. Roll out the dough on baking paper dusted with flour to the size of a baking sheet, then bake in the oven for 10-20 minutes at 160 ° C until light yellow.
Spread jam on the hot dough.
Roll out the marzipan with a little icing sugar as large as the sheet of dough and place on the jam. Brush the marzipan blanket with egg white. Bake for 10-15 minutes at 160 ° C until the surface is slightly yellow but not browned.
For the chocolate glaze, melt the chocolate and butter together in a double boiler.
After cooling, cut the marzipan dough into 3 x 3 cm squares. Dip diagonally halfway into the dissolved chocolate icing.