@chuck s start by whisking an egg and milk together. Add dry ingredients (flour, salt, pepper and any spices you like - we used a bunch of cayenne and paprika) until you have a really thick and pasty batter. Dip the chicken in flour, then in the batter, then dip in melted butter or cooking oil (I'm sure Pam or another cooking spray would also work). I didn't really measure and had to add more milk and flour on multiple occasions to have the right consistency and enough batter to cover the chicken.
Cook high indirect heat (450 degrees or so) for 45 minutes to an hour until it looks like fried chicken. The chicken's internal temp on the Thermapen was about 200 degrees by the time the batter was done, and it was still really juicy inside. I don't think you would have had the "fried-like crunch" if you pulled it earlier.
Think of batter thickness that would kind of stick to the bowl for a few seconds if you turned the bowl upside down - not dry like dough, but a very thick, sticky batter. Hope that helps! Let me know if you have any more questions.