PREPARING THE DOUGH Place all of the dough ingredients (all-purpose flour, sour cream, egg, extra virgin olive oil, and kosher salt) in a bowl and mix together. Once the dough has formed, place it on a lightly floured surface. Knead until a smooth dough has formed. Wrap the dough in plastic wrap, and let it rest for 30 minutes on the counter.

PREPARING THE ONIONS Heat a large saute pan with 2 tablespoons of grapeseed oil and 2 tablespoons of butter. Once the butter has melted, add in the julienned onion, and saute. Sprinkle the onion with kosher salt, and cook for 15-20 minutes until caramelized, while stirring occasionally. Remove the cooked onions from the pan, and reserve.

PREPARING THE POTATOES/FILLING Place the peeled and cut potatoes in a large pot covered in cold water, and add in 1 teaspoon of kosher salt. Bring the water to a boil, and reduce the heat to medium-low. Simmer for 10-15 minutes until the potatoes are tender. Drain the potatoes well, and mash. Add a 1/4 cup butter and 1/2 of a teaspoon of kosher salt to the potatoes, and mix until blended. Season to taste with kosher salt.

PREPARING THE PIEROGI On a lightly floured surface, roll the dough out, making it an 1/8 of an inch thick. Using the round cutter, cut out as many rounds as you can. Knead the scraps of dough, and cover it with plastic wrap. Let the scrap dough rest for 10 minutes while making the first batch of pierogi. Place 1 tablespoon of the mashed potatoes/filling in the center of each dough round. Dip your finger in water, and run it around the outside edge of the pierogi.

Fold the dough over, making a half moon. Press out the air, and flatten the filling. Crimp the edges with a fork, and place the sealed pierogi on a parchment-lined baking sheet. Repeat these steps with all of the dough rounds. Then, roll out the scrap dough, and repeat the process (fill and seal the second batch of dough rounds).

Bring a large pot of salted water (3 quarts of water and 2 tablespoons of kosher salt) to a boil. Boil off 8 pierogi at a time for 3 minutes. Then, drain. Repeat the process until all of the pierogi are boiled off.

FINAL STEPS Heat 2 tablespoons of butter in a large saute pan. Add in a third of the Wagyu beef smoked kielbasa sausage (that has been cut on a bias into 1/8-inch-thick pieces). Cook for 1 minute. Then add in 6-7 of the pierogi with the kielbasa. Brown the pierogi on both sides, and toss with a third of the onions and a couple pinches of kosher salt.

Remove from the pan, and repeat the process with 2 tablespoons of butter, a third of the kielbasa, 6-7 pierogi, a third of the onions, and kosher salt. Remove them from the pan, and repeat the process for the last time with 2 tablespoons of butter, a third of the kielbasa, 6-7 pierogi, a third of the onions, and kosher salt. Garnish the pierogi and Wagyu beef kielbasa with minced scallions. Serve hot, and enjoy!