Heat oven to 220C/fan 200C/gas 7. Place the leeks in a microwaveable bowl with a splash of water, then microwave for 3 mins on High. Set aside. Microwave the potatoes for 10-15 mins on High, turning halfway through cooking. Leave until cool enough to handle, then cut in half lengthways and carefully scoop out the middle into the bowl with the leeks, keeping the potato skin intact.
Mash the leek and potato with the soft cheese, egg and parsley, then spoon back into the potato skins. Place on a baking sheet, then bake for 15 mins until the filling is golden brown and piping hot, and the skins have crisped up. Delicious served with a tomato and baby leaf salad.