I've tried making pizza twice on my large egg.twice. I placed my official BGE pizza stone on the grill and set the temp to 425 degrees. I gave it about 20 minutes for the temperature to stabalize and then cooked the pizza for 20 minutes. The crust was burnt to a crisp and inedible both times. What did I do wrong? I made the dough from scratch. Could I have done something wrong there that would cause burning?