Preheat your oven to Gas Mark 6/200°C.
Wash the potatoes and prick with a fork, place on a baking tray and cook in the oven until cooked - they should be soft inside with crispy skins (approx 60-80 minutes).
Place the mince in a non-stick wok or saucepan and dry fry until browned for about 6 minutes.
Add the onion and garlic and cook for a few minutes more.
Add tomatoes, puree or ketchup, stock, herbs and pepper.
Cook gently over a low heat for 15 minutes.
When the potatoes are ready cool slightly, cut in half and using a spoon, scoop out the soft inside into a large bowl. You may need to hold the potato with an oven glove.
Mash the potato, add the butter and black pepper. Put a spoonful of the bolognaise mixture into each potato skin, mix the rest with the potato mixture and spoon back into the shell. Sprinkle the grated cheese on top of the potatoes.
Pop them back into the oven for 10-15 minutes until they look crispy and golden.
You could serve any left over sauce with cooked spaghetti as spaghetti bolognese or cool the mixture slightly to make mini pizzas or bolognese jacket potatoes