For Dalmatian slices, place flour with powdered sugar on a work surface, press a hollow in the center and spread cold butter in pieces all around. Add eggs, yolks, vanilla sugar and quickly knead all ingredients into a smooth dough. Wrap in aluminum foil and let rest in the refrigerator for 2 hours.
For the filling, beat egg whites with powdered sugar and vanilla sugar until very stiff, fold in grated almonds and fill the mixture into a piping bag.
Place baking paper on a baking sheet and roll out the dough to the length of the baking sheet and a width of about 12 cm. Press a raised edge all around and brush this with whisked yolk.
Use a pastry bag to pipe the almond snow mixture in a serpentine pattern. Bake in a preheated oven at 160 degrees for 30 minutes. Remove the hot Dalmatian slices from the baking sheet, let them cool on a cooling rack and portion them.