For the Dough:
3 1/3 cup All-Purpose flour
3 heaping Tablespoons sour cream
3/4 cup hot water
1 whole egg
In a stand mixer fitted with the hook mix the dough for 10 minutes.
When a soft smooth ball has formed, wrap tightly in plastic and let rest for 1 hour in cooler.

Filling:
1 lb. russet potatoes, peeled, quartered and rinsed
1 cup Shard cheddar cheese, grated
1 yellow onion
1 cup butter

Place the potatoes in a pot and cover with cold water. Add a good amount of salt and bring to a boil, and then reduce to a simmer.
When potatoes are fork tender, strain and lay potatoes out on a sheet tray and allow to cool at room temp. Let the water evaporate off.
Meanwhile, melt the butter. Add onions and sweat, no color until translucent. Keep warm.
While the potatoes are still warm place them in a stand mixer fitted with the paddle and beat the potatoes, onions and butter and cheese until fairly smooth. Taste and adjust seasoning.
Chill this down completely.

To make pierogi:
Roll dough out on a well-floured surface. Using a 4” ring mold stamp out rounds.
Place 1 T of filling on each round disk dough.
Wet one side of dumpling with a little water and use your fingers to pinch dough around potato into a half moon shape. Repeat until all filling is gone.
Boil pierogis in salted water until they float.

                                    Bon Appétit