1 medium onion, cut in half and sliced thin
2-3lb. corned beef brisket with seasoning package
12 oz. can / bottle beer (I used Angry Orchard Apple Ginger)
2 Tbs. yellow mustard
1/4 c. brown sugar
1 c. water
1/2 head cabbage, sliced
Place the onions on the bottom of the slow cooker. Rinse the beef off and pat dry with a paper towel. Place on top of the onions and rub the dry mix on top. Pour the beer over. Mix the yellow mustard, brown sugar and water together and pour on top of the beef. Cover and cook on low for 9 1/2 - 10 hours.
Remove the beef from the crock pot and let sit with tinfoil on top. Add the cabbage to the slow cooker and cook in the liquid for 25-30 minutes until the cabbage is fork tender. Cut the corned beef across the grain and serve on top of the veggies. Spoon some of the cooking liquid on top to keep moist.