Divide the dough into 8 equal pieces and turn them into balls. They should weigh approximately 95 grams each.
Take a dough ball and roll it out into a 10 cm Ø circle on a lightly oiled surface.
Spread the ⅛ of the soft butter on the dough circle and fold it from the sides to form a square parcel.
Repeat with the remaining dough balls, transfer them on a plate or tray, cover with cling film and refrigerate them for 15 minutes.
Take them out of the fridge and roll them out into a square shape of approximately 20 cm.
Fold them again into small square parcels and refrigerate for another 15 minutes. Repeat the same procedure 2 more times (3 folds in total).
Preheat the oven to 170 °C.
For the filling, mix sugar and tahini in a bowl.
Take the pastries out of the fridge, place 1 square parcel on a lightly oiled worktop and roll it out into a 20 cm square.
Spread ⅛ of the tahini on the pastry, sprinkle on the walnuts and the chocolate.
Gently roll the dough into a log shape.
Cut the log into 4 pieces. Repeat the same with the remaining 7 square parcels. You will have 32 small pastries in total.
Place them on a baking paper lined trays.
Mix the egg yolk with yoghurt in a small bowl and eggwash the pastries with a pastry brush.
Sprinkle on sesame seeds and bake them for 25 to 30 minutes or until golden brown.