Place the beef, onion and garlic in a saucepan and fry for 8-10 minutes, stirring occasionally. Add the stock, tomato puree, most of the herbs, cornflour and water mix and season to taste. Bring to the boil and simmer gently for a further 5minutes, stirring until thickened. Transfer to an ovenproof dish. Mash the potatoes with the butter, milk, most of the cheese and season to taste. Spoon or pipe onto the meat and sprinkle with the remaining cheese (mixed with the last of the herbs). Bake for 25minutes of until golden brown. 200c/400f/gas mark6.
