In a large pot, cover potatoes with cold, well salted water by 2 inches. Bring to a boil, reduce heat so that the water slowly simmers and cook until tender, about 15 minutes. Drain well. Let potatoes sit 5 minutes.

Return potatoes to pot. Add butter and mash until smooth. Season with salt and pepper.

Stir in two egg yolks,  and 1/4 c heavy cream.

Line a baking sheet with parchment and butter lightly. Using a 1/2 c measure, drop 8 to 10 portions on parchment. Using the back of a spoon, create a small well in the center of each portion. Freeze until firm, about 15 minutes.

These may now be taken off of baking sheet and frozen in a large zip lock bag.

OR…preheat oven to 450. Whisk remaining egg yolk and 2 t cream. Brush on potatoes and bake until golden, about 15 minutes.