8 to 10 peeled potatoes
1/2 stick butter
1 1/2 tsp. salt
1/4 tsp. pepper
1 1/2 c. sour cream
1/4 c. chives, chopped (optional)

Cook potatoes in salted water until tender. Drain and mash. Add remaining ingredients. Beat with mixer until blended. Pile lightly in a buttered casserole. Cover and refrigerate overnight. Remove 15 minutes before baking. Uncover and bake 30 minutes at 350 degrees.