Set your crock pot on high setting.
Place the corned beef into the crock pot and add the broth, Guinness and onion.
Add the bay leaves and sprinkle the garlic powder and pepper over the corned beef.
Place the lid on the crock pot and cook for 3 1/2-4 hours.
Remove the lid and add the potatoes, carrots and cabbage.
Replace the lid and cook for a further 1 hour or until the corned beef has reached 145 degrees and can be poked witha. sharp knife easily.
Remove the corned beef from the crock pot and place on a cutting board.
Cover with foil and let rest for 10 minutes before slicing.
Serve with some of the vegtables and wholegrain mustard on the side.