Beer Braised Corned Beef with Whiskey Mustard Glaze

to 5 pounds flat cut corned beef brisket (, rinsed)

large yellow onion (, halved and sliced)

garlic (, peeled and lightly crushed with the back of a knife)

lager ((nothing with heavy bitter notes))

water (, plus additional (if needed))

pickling spice ((or use the spice packet provided with your corned beef))

dark brown sugar (, lightly packed)

whole grain Dijon mustard

smooth Dijon mustard

whiskey

freshly-ground black pepper

ground cloves