Preheat oven to 400 degrees. Lightly butter a 9x13 inch pan and set aside.
In a large pot, bring potatoes to a boil and cook for 15-20 minutes until tender. Drain.
Add 10 tablespoons butter, sour cream, salt and pepper to the potatoes and mash. Add the chives. Spread in your 9x13 inch pan.
To make the topping, combine bread crumbs, parmesan cheese, and 4 tablespoons butter. Mix together until it forms course crumbs. Sprinkle on top of the potatoes.
Bake for 30-40 minutes until it is golden and crisp. Serve hot.