Sous vide and finished on Big Green Egg.
I put it in a ziplock with butter, salt, pepper, garlic, onion and let it cook sealed at 120 degrees for 3 hours. I came back and lit up the grill to get the lump charcoal get as hot as I could get it by leaving the lid completely open. I then seared the outside until I got a good char and that was it.
We also had baked potatoes and onions also on the big green egg to go with it.