For the almond slices, mix flour with a pinch of salt, crumble with butter and quickly knead with sugar, egg and lemon zest. Wrap in foil and let rest in a cool place for 30 minutes.
Preheat the oven to 180° C, cut baking paper to the size of a baking tray and dust with flour. Roll out the dough on the paper to a thickness of about 5 millimeters, place on the baking tray and bake for about 10 minutes.
Beat butter with sugar until creamy, add eggs gradually. Mix in almonds and a few drops of flavoring. Mix jam until smooth and spread with a brush on the pre-baked dough, spread almond mixture evenly on top and finish baking for another 15 to 20 minutes.
When cooled, cut almond slices into narrow strips and dip in chocolate icing on one side.