Irish Beef Stew [slow cooker]. [Slow cooker version]. The original Irish Stew consists of neck of mutton, almost as much potato as meat, and sliced onions arranged in layers and stewed.I make this beef version exactly as it was passed on to me by my mum.rish Beef Stew [slow cooker]. [Slow cooker version]. The original Irish Stew consists of neck of mutton, almost as much potato as meat, and sliced onions arranged in layers and stewed.