Meat Stew: In a large saucepan brown the mince, while stirring add the stock cubes. When fully brown add the onion and garlic stir.
Pour in the water then add the the carrots and celery then bring to a gentle boil.
Combine the 1/2 cup water, gravox and cornflour. When the carrots and celery are softened stir in the gravox mix stirring continually until a thick gravy has formed. If too thick add additional water to get the consistency you prefer.
Potato: Bring the water, milk and butter to a simmer. Stir in the instant potato and garlic powder.
To Assemble: Carefully spoon the mashed potato over the beef stew, even out with a fork if required. Sprinkle with the grated cheese.
Preheat the oven to 180 degrees C and cook the shepherd's pies until the cheese melts