Prepare the vanilla dough by mixing butter, powdered sugar, egg yolk, vanilla, cornstarch, and flour
Prepare the chocolate dough by mixing butter, powdered sugar, egg yolk, instant coffee with boiled water, vanilla, flour, cornstarch, and cacao powder
Leave both doughs in the fridge for 20 minutes
Place vanilla dough between nylon and spread it out with a rolling pin and shape it
Take the chocolate dough and spread it and shape it in the same way
Cut both doughs into 3 strips
Place the layers on top of each other
Cut in half again and place the layers on top of each other
Cut into biscuit sizes
Place biscuits in the oven tray
Bake in the oven for 15 minutes at 170°C or 340°F
Dip the edge of each biscuit into the melted chocolate
Sprinkle pistachio powder on top
