For the walnut bites, cream butter with yolks, sugar and honey until fluffy. Mix in the Nutella. Mix in nuts, baking powder and flour.
Fill the soft dough into a piping bag and pipe small heaps with a round nozzle onto a prepared baking tray. Press half a walnut into the center of each mound.
Let rest in a cool place for 1 hour before baking. Bake the walnut buns in the preheated oven at 165 to 175 °C for about 10 minutes until light brown.