Preheat oven to 375°.
Dissolve beef bouillon cubes in boiling water, and set aside. Grease cookie sheets.
In a large bowl, stir together the brown rice flour, corn meal, brewers yeast, and garlic powder. Add the yolks, then gradually pour in the beef broth 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 for 20 minutes in the preheated oven, 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.