Preheat oven to 400°F (200°C).
Place boiled potatoes in a large bowl and mash with a potato masher or fork.
Add melted butter, salt and pepper and mash until well combined.
Add cream cheese and sour cream and mix/mash until well mixed.
Mix in ⅔ of the shredded cheese.
Place potato mixture in an oven safe dish and top with the remaining cheese. Bake for 25-30 minutes at 400°F (200°C), until browned and crispy on top.
Top with chopped chives before serving.
