Place peeled potatoes in a large pot half full of cool, salted water. Cover and bring to a boil, reduce heat to MEDIUM and continue cooking until tender, approximately 30 minutes. Meanwhile, chop green onions, and combine with cream cheese, sour cream, salt and pepper.
Drain potatoes, place into a large mixing bowl with butter and mash with a potato masher. Add cream cheese mixture and beat with an electric mixer until fluffy. Spoon mixture into a buttered aluminium tray or pan and sprinkle with Parmesan cheese. Can be refrigerated overnight at this point, covered tightly.
Place in an oven or barbecue, preheated to 350°F (177°C). Bake, uncovered, until golden brown, approximately 40-50 minutes.
NOTE: Can be prepared up to 2 days in advance and heated in the barbecue or oven, when needed.
