Heat the oil in a large frying pan over high heat. Add the mince and cook, undisturbed, for 3 minutes to brown the mince. Use a wooden spoon to break up the meat, and continue to cook for further 5 minutes, until browned and cooked through.

Stir through the mushrooms and cook for a further 2 minutes, then stir and cook until the moisture has evaporated. Remove the mushroom and mince mixture to a medium bowl and set aside.

Return the pan to the heat, then add the onion, garlic and carrot and cook for about 2 minutes, until beginning to soften. Season with salt and pepper. Stir in the flour, tomato paste, Worcestershire sauce and wine and cook for a further minute. Return the mince mixture to the pan, crumble over the stock cubes and pour in the hot water.

Bring to the boil, then reduce the heat to low. Cook, stirring occasionally, for 15-20 minutes or until thickened. Season with salt and pepper.

Meanwhile, preheat the oven to 200˚C (180˚C fan-forced). Place the potatoes into a large saucepan and cover with water. Bring to the boil over high heat, then boil for 12 minutes, or until tender. Drain. Return to the pan over low heat. Mash until smooth, then fold through the milk, sour cream and 100 g of diced butter. Season with salt to taste.

Stir the parsley through the mince filling, then spoon the mixture into a 2 litre (8-cup) ovenproof baking dish. Spoon over the prepared mash, using a spatula to make a decorative pattern, if you like. Drizzle over 50 g melted butter, then bake for 20 minutes, or until the topping begins to brown. Remove from the oven and allow to stand for 15 minutes, then serve.