Made this for my partner as I don't eat meat, he loved it! My supermarket had run out of Guinness so I used sweetheart stout, that worked fine. The only change I made was using the excess fat from the lamb mince instead of butter as the gravy base. I doubled it, which made two of the dish pictured. It's a labour of love, but most pie recipes are, and this one is worth doubling as he'll happily eat this for a fortnight.
