First make the filling. In a flameproof casserole heat 1 tbsp. Oil until very hot, then brown the beef well on all sides in batches, adding more oil if you need it. Remove the beef from the pan and reduce the heat a little, add a touch more oil and soften the onion for 2-3 minutes, adding the garlic and then the carrots and
mushrooms. Fry for about 5 minutes to allow the vegetables to soften but not brown too much.