Remove any fat from the meat and slice into 2x6cm strips. Slice the mushrooms in 4 and set aside. Place the meat, cornflour, mustard, cinnamon and vermouth in a bowl and mix well. Place the onions, meat mixture and stock in the slow cooker and cook for 3-4 hours on high or 6-8 on low. Add the mushrooms, salt and pepper 1 hour before serving and crème fraîche half an hour before serving. See more Beef recipes For top tips on protecting you and your family when preparing raw meat and poultry, visit Food Safety in the Home.