Wash potatoes, pierce with a fork all over and bake in oven for 60 minutes, or until soft.
Whilst potatoes are baking start preparing the mince filling. Place the mince and onion in a large frying pan to brown. Drain off excess fat, then add water and bring to the boil. Crumble in stock cubes and simmer and reduce until most of the water has evaporated.
When ready, add enough gravy granules to thicken. Then remove from heat.
Once the potatoes are cooked, remove from oven and cut in half. Scrape out the insides of the potatoes into a bowl and set the skins to one side.
Using a potato masher, mash the potato with the butter and milk to make a smooth mash.
Fill the potato skins 3/4 full with mince, then top each with mashed potato.
Put back the potatoes back in the oven until the top of the potato is crispy and brown.
For an extra twist put grated Cheddar and bacon into the potato mix before stuffing into the potato. Or for a healthier option use turkey mince and no butter or milk in the potato.