Slow Cooked Beef Stroganoff

450ge beef brisket 52.0% , stroganoff sauce 24.9% , single cream 11.6% , portobello mushrooms 5.8% , water 2.9% , onion 1.4% , brandy 0.7% , salted butter 0.4% , modified corn starch 0.2% , beef broth 0.1% , white wine vinegar 0.0% , dijon mustard 0.0% , brown sugar 0.0% , garlic puree 0.0% , tomato concentrate 0.0% , yogurt powder 0.0% , Mushroom stock 0.0% , salt 0.0% , yeast extract 0.0% , parsley 0.0% , Colour 0.0% , black pepper 0.0% , smoked paprika 0.0% , water 0.0% , modified corn starch 0.0% , beef broth 0.0% , Colour 0.0% , salt 0.0%