David can help with this.
Use 12" DO.
Prepare presorted bag of briquettes.
Stir together the cookie mix, eggs and butter in bowl.
Line DO with parchment.
Press the batter into the bottom of the lined DO.
Cover with the lid.
Put 1/3 of the coals on the fire pan, put the DO on the coals, and the remaining coals on the lid.
The cookie bakes in about 45 minutes or up to an hour. Mostly, if it's aromatic, it's close to done.