Place the corned beef in the bottom of your slow cooker (I recommend using a 5 quart or larger slow cooker). Add the contents of the spice pack that came with the corned beef, along with any additional spices if desired. Add the remaining ingredients except for the cabbage. Cover and cook on high heat for 5 hours or low heat for 8 to 10 hours.
30 minutes to 1 hour before serving, add the cabbage to the crock pot - gently push it down into the liquid as best you can. If there isn't room at first, no big deal - you can wait until the cabbage cooks down a little and then push it further into the liquid.
Remove the corned beef from the slow cooker and place it on a cutting board. You can either slice, shred, or chop it into chunks. If you have time, place the meat back into the slow cooker for at least 30 minutes so that it soaks up the juices
Serve the corned beef with the cooked vegetables and cabbage, and enjoy!
* You can use a wide variety of beers for this recipe, but I would recommend not using anything too hoppy like an IPA. Generally, porter, stout, blonde, or amber ale work great! If you're gluten-free, use a gluten-free beer like Omission. You can also replace the beer with more broth.
**You can replace the chicken broth with beef broth or another beer.