For the liver cookies for dogs, knead all ingredients into a smooth dough. Let rest for about 1/4 hour. Roll out the dough (this is best done between two sheets of plastic wrap) and cut out with a cookie cutter or cut into lozenges.
Bake in the oven at 150 °C convection oven for about 25 minutes. Leave to cool in the oven with the oven door slightly open.