Roast the whole potatoes for 20 - 30 minutes or until just tender when pierced through the centre with a skewer.
Turn the oven to the grill element.
Cut an incision into each potato, ensuring not to pierce through to the bottom. Squeeze to expose potato flesh. Place the cheese, sliced sausage and jalapeño into the potato. Place the potatoes back onto the tray and cook in the oven for 10-15 minutes or until potatoes are golden.
Add a dollop of mustard on top and serve as finger food.