Put the Amarettini in a small freezer bag and crumble them with a rolling pin. Heat butter in a pan and lightly toast the amarettini crumbs while turning. Remove from the pan and let it cool down. Mix quark, milk, oil, sugar, vanillin sugar and salt. Mix flour and baking powder and stir about half into the quark mixture. Knead in the remaining flour. Form the dough into a thick roll on a floured work surface and cut into 8 equal pieces.
Press each piece slightly flat with your hands and make a hollow in the middle. Put thalers on a baking tray lined with baking paper (approx. 32 x 37 cm) and fill each with some strawberry jam. Mix egg yolk and milk. Brush the edges of the thalers with the mixture. Sprinkle with amarettine crumbs and press down lightly. Bake in the preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for 15-20 minutes. Let the thalers cool down on a cake rack and arrange them on a large plate