Put the beef, garlic powder, bay leaves and peppercorns in a 6 quart Dutch oven or large pot. Fill the pan with enough water to cover everything plus 1 inch. Bring it to a boil and cook for 20 minutes. Skim off any floating residue.

Lower heat to a simmer, and cook for 2 to 3 hours or until the brisket can be pulled apart with a fork.

Add the carrots, potatoes, and cabbage. Simmer for another 15 minutes or until the potatoes are tender. Skim off any fat that floats to the top, and add the parsley and butter. Remove the pot from the heat.

Transfer the brisket from the pot to a serving dish, and let the meat rest for 15 minutes. Transfer the vegetables to a separate serving bowl an keep it warm. Slice meat diagonally against the grain. Serve with juices spooned over the meat slices and vegetables.