Preheat oven to 300° F.

Grease (or line with parchment paper) 2 large cookie sheets. Mix dry ingredients in a large bowl. Add the egg, oil and stock. Mix well to form a soft dough that is firm enough to roll out. On a floured surface roll out dough to about 1/2 inch in thickness. Cut into desired shapes and place about 1 inch apart on the prepared cookie sheet. Bake for two hours, then turn the oven off and let the biscuits sit for several hours until oven is completely cool in order to dry and harden them. Store at room temperature for several months.