I have found the best way to insure Corned Beef turns out tender is to start out with a very good quality, such as Harrington's. Then, buy a very good quality slow cooker such as the Cuisinart 4 qt.
I cook my corned beef and just the carrots in the slow cooker. I sauté the cabbage and sweet onion in butter separately in a large skillet.
Serve it with Irish Soda Bread & Kerry Gold Irish Butter.
Turns out great, year after year.
Sheila |