Preheat oven to 190°C.
Place the potatoes on a lined baking tray and prick with a skewer a couple of times. Bake for 75 minutes until soft.
Meanwhile, cook the onion in a little oil in a non-stick frying pan for 2-3 minutes, add the broccoli and carrot and then continue cooking for 3-4 minutes until softened, being sure not to brown. Stir through the corn, ham (if using) and parsley then remove from heat.
Remove the potatoes from the oven and allow to cool slightly then slice in half. Scoop out the flesh, being careful not to break through the skin.
Mix together the scooper potato, broccoli mix, half the cheese and sour cream. Season with salt and pepper.
Spoon the mixture into the cavities of the potatoes and sprinkle with remaining cheese.
Bake for 20 minutes of until golden. Allow to cool for 5 minutes, then serve with a simple salad if desired.