4 large white potatoes
6 tbsp sea-salted butter, cut into pieces
1 1/4 cups whole milk
3 large egg yolks
Salt and white pepper
Black sesame seeds or caraway seeds
Peel the potatoes and cut them into chunks; cook them until tender in salted boiling water, then drain them well. While the potatoes are cooking, place the milk and the butter in a saucepan and heat until the butter melts; set aside. Drain the potatoes and mash them with the milk and butter; add the egg yolks and season to taste with salt and white pepper, beating until well combined. Butter a 1 1/2 quart shallow baking dish and set it aside. Place the mashed potatoes in a pastry bag (or a heavy plastic zip-lock bag—cut off a corner just before piping) and pipe the potatoes, close together, into 2 1/2 to 3-inch high mounds to form “ghosts”. Decorate the top of each with two seeds for eyes and bake in a preheated 400 oven until the tips of the ghosts are golden and the potatoes are firm, about 25 minutes.