Place potato in a large saucepan. Cover with cold water. Bring to the boil over high heat. Cook for 10 to 15 minutes or until tender. Drain well.
Return potato to pan over medium heat. Toss for 1 minute or until excess liquid has evaporated. Remove from heat. Mash until smooth. Stir in butter, milk, 4-cheese blend and green onion until combined.
Grease a 9cm-deep, 21cm-round (base) baking dish. Preheat grill on medium-high heat. Spoon mash into prepared dish. Smooth top. Sprinkle with breadcrumbs and parmesan. Season with pepper. Grill for 5 to 10 minutes or until top is golden and crunchy. Serve.
Recipe courtesy of www.taste.com.au
Serving size 4