Remove the corned beef from the package and give it a quick rinse. Careful not to remove any of the seasonings attached to the corned beef.
Place the corned beef in a large stock pot and pour in 1 can of beef broth. Then pour in enough water to cover the corned beef by 2-3 inches above the meat . If at any time the water level should fall below the meat, just simply add in more water.
Bring to a boil, reduce heat to medium-low, cover with a lid and simmer for 3 hours.
Then add a whole peeled yellow onion into the pot. Place the lid back onto the pot and continue to simmer for another 1 ½” hours. It should be about 4 ½” hours total simmering time. Estimated 90 minutes per pound. Remove from the pot once you are able to easily pierce the thickest part of the corned beef with a fork. Vegetables such as carrots, potatoes or cabbage can be added during the last 30 minutes of simmering.
When done, remove the corned beef from the pot and place on a cutting board. Slice across the grain into thin slices .
( Optional ) Reserve some of the broth from the pot. Right before serving, dip the slices of corned beef into the hot broth. Then serve on a plate.