1) Cut the beef into 2.5cm chunks, removing any gristle.
2) Melt the dripping in a saucepan and fry the meat until browned on all sides.
3) Peel and roughly chop the onions, and peel and slice the carrots. Add them to the pan with the stock pot, water and Guinness.
4) Add the thyme, puree and halved garlic bulb.
5) Bring to a simmer and cook for 1½ hours.
6) Add the potatoes and cook for a further 30 minutes or until the beef is tender.
7) Saute the button mushrooms in the olive oil and add to the stew at the end.