Golden Gate Potato Casserole

1/4 cup butter
2 cups shredded Cheddar cheese
1 teaspoon salt
1/3 cup chives
1 pint sour cream
1/8 teaspoon pepper

Melt butter and cheese in a saucepan. Remove from heat and add sour cream, chives, salt and pepper. Fold into 8 coarsely-mashed potatoes and put into a greased casserole. Cover and bake at 325 degrees F for 25 minutes. Uncover, sprinkle more grated cheese on top, and return to oven just until cheese is melted.