1 large red onion peeled and sliced into six large thick slices
4 large garlic cloves, smashed
2 tablespoons olive oil
1 12-ounce bottle dark ale beer
½ cup ketchup
2 tablespoons stone ground mustard
3 tablespoons Worcestershire sauce
1/3 cup brown sugar
In a small bowl, mix salt, pepper, chili powder, garlic powder, ground coriander and mustard powder.
Rub this mixture all over the pork and then place in a gallon zip lock bag. Refrigerate for at least four hours or overnight.
Three hours before serving, heat grill to high on one side and the lowest burner setting on the other.
Place the onions and garlic in a 5 quart Dutch oven that has a lid. Place that on the cool side of the grill.
Once the hot side is hot, place the pork butt on a plate and brush all sides with the oil. Then place on hot grill and sear all sides, about 10-15 minutes total. The char on all sides should be nice and dark, even black in spots.
Lift the meat with tongs and place in the Dutch oven on top of onions and garlic.
Pour the beer over the top of the meat and place on cover.
Shut off all burners except the one under the meat and set that to as low as it will go and close grill cover. Our one burner on low maintained a temperature inside the grill of 275 degrees F.
After three hours, remove lid with pot holder and check for tenderness of meat by pulling off a small piece and trying it. Meat should be fall apart tender.
Remove the meat to a clean platter to rest.
Take the liquid left in the pan and skim off any fat floating at the top and discard.
To the remaining liquid, add catsup, mustard, Worcestershire sauce and brown sugar.
Increase the burner to bring the mixture to a boil, then lower to a medium simmer and simmer between 10 and 20 minutes or until thick. (This step can be done indoors on your stove top if you wish).
Once the sauce is done, shred the meat with two forks and add back into the pot with the sauce.