Gourmet cheese and onion spuds

Wash and dry potatoes. Rub lightly with margarine (this will give them a shiny, crispy shell when cooked).
Place in a cold oven. Set temperature at 200 ºC and bake for 1 1/4 to 1 1/2 hours, or until cooked through and crisp.
Meanwhile, heat butter and oil in a pan and sauté onions until golden. Set aside.
Mix remaining ingredients, except Parmesan cheese, together. Add onion to cheese mixture.
When potatoes are done, halve them and scoop out flesh. Add flesh to cheese mixture and mix well. Pile mixture back into potato shells, sprinkle with Parmesan cheese and grill for a minute or two.
Serve immediately, with a huge mixed salad.
TOTAL KILOJOULE COUNT: 8 270 kJ (1 975 Cal). A portion: 2 070 kJ (495 Cal).