In a medium bowl, mix flour, cracked wheat, corn meal and powdered milk. In a large measuring cup mix egg, broth, molasses and garlic powder. Add to dry ingredients and mix well. If dough is too soft; add a bit more flour. If dough is too stiff; add a bit of water. Pat out on floured board to about 1/4" thick. Cut out with small cookie cutters. Place on an ungreased cookie sheet. Brush tops with milk. Let air-dry for 30 minutes before baking. Bake at 325 degrees for 50 minutes. Turn oven off, but leave the cookies inside for 1-2 hrs. to get crunchy.