Preheat the oven to 375 degrees F (190 degrees C). Grease cookie sheets.
Dissolve beef bouillon cubes in boiling water and set aside.
In a large bowl, stir together whole wheat flour, corn meal, brewer's yeast, and garlic powder. Add egg yolks, then gradually pour in bouillon water mixture while stirring. Mix thoroughly to form a firm dough. On a floured surface, roll the dough out to 1/4 inch thickness. Cut into desired shapes using cookie cutters. Place cookies one inch apart onto cookie sheets.
Bake in the preheated oven for 20 minutes, then turn the oven off, and leave the cookies inside for at least 3 hours or overnight to harden. Store in an airtight container at room temperature.