Preheat the oven to 180°C, fan 160°C, gas 4. Put the potatoes in a bowl, prick each one once with a fork, add the oil and use your hands to rub it all over the potatoes.
To make the bolognese, heat the oil in a saucepan and add the onion, pepper and carrot. Cook, stirring occasionally, for 9 minutes until soft. Transfer to a plate. Add the mince to the pan and brown all over for 5 minutes.
Add the vegetables back into the pan with the passata, 500ml water, the sugar and vinegar and leave to simmer for 40 minutes, stirring occasionally. until most of the liquid has reduced.
Meanwhile, bake the potatoes for 40 minutes until the skins are crisp and the insides fluffy.
Cut a slit in each potato and fill with a little bolognese. Sprinkle the chopped parsley over the top and serve on a platter.
Cook's tip: add a pinch of paprika for a little kick.