Dough rolled about 1/4" thick and then cut with a cookie cutter? or thicker?
Did you try cooking at a lower temperature (about 200*) for a longer period of time, then turning off the stove and leaving them in the oven over nite?
You could also try cooking at a slightly lower temp then the recipe calls for (so they won't burn), flipping them when they are done, then, turn down oven to about 125* and cook them a while longer to dry them out. Then leave in oven until it's cool.