1. Preheat oven to 400 degree F. Brush a jelly-roll pan lightly with some of the butter. Slice the potatoes 1/2-inch thick, discarding ends. Arrange the potato slices on the prepared pan. Brush with the remaining butter and sprinkle with salt and pepper. Bake for 15 minutes. Turn potatoes and bake about 10 minutes more or until tender and golden.
2. Transfer potatoes to a serving platter and keep warm. To serve, spread 1/2 teaspoon sour cream on each slice and top with 1/4 teaspoon lumpfish. Makes about 24 appetizers.