Step 1

Make the Dough: In a large bowl, stir together the egg, water, and salt until fully combined. Gradually mix in about 2 ⅔ cups of the flour and stir to combine into a shaggy dough. Turn it out onto a floured surface. Knead the dough with the heels of your palms for about 5 minutes, until it is smooth, elastic, and no longer sticks to your hands, sprinkling on more flour as needed. Place the dough back in the bowl, cover loosely with a kitchen towel, and let it rest for 30 to 60 minutes.

Step 2

Meanwhile, cook the Potatoes: Place the potatoes in a medium pot with enough water to cover by about 2 inches and a teaspoon of salt. Cover, bring to a boil, reduce the heat to low, and simmer with the lid ajar until the potatoes can be pierced easily with a fork, about 15 minutes.

Step 3

Cook the Onions: Heat the oil in a large skillet over medium heat. Add the onions and cook, stirring frequently, until they’re dark brown and a bit crispy, about 15 minutes. Set the skillet aside.

Step 4

Finish the Filling: Reserve 1/3 cup of the potato cooking water, drain the potatoes, and return them to the pot. Mash until smooth and stir in the reserved cooking water and a third of the fried onions with their oil. Season to taste with salt and pepper. Bring the potatoes to room temperature.

Step 5

Roll out the Dough: Cut the dough into 4 pieces. Working with 1 piece at a time (keep the remaining dough in the bowl covered with the towel), roll the dough between your palms into a thin log about 10 inches long and 1 inch thick. On a floured surface, cut the log into approximately 12 1-inch pieces (these should resemble gnocchi). Using a rolling pin dusted with flour, roll each piece into an approximately 3-inch circle; if the dough is sticking to the surface or rolling pin, dust it with more flour.

Step 6

Fill the Dough: Working with 1 circle of dough at a time, place a heaping teaspoon of the potato filling into the center. Gather the dough into a half-moon shape around the filling and pinch the top closed, then pinch both edges closed. Place the shaped varenik on a well-floured board or tray and continue filling the rest of the dough. Make sure the varenyky are not touching – you do not want them to stick together.

Step 7

Boil the Varenyky: Bring a large pot of generously salted water to a boil. Boil the varenyky in batches – 6 to 10 at a time, depending on the size of your pot. Cook them for 2 to 3 minutes – they are done when they’ve floated to the surface, the water returns to a simmer, and they’ve been simmering for about 30 seconds. Do not overcook, as the filling may escape the dough.

Step 8

Using a small mesh strainer or slotted spoon, fish the varenyky out and place in a large bowl. Add a small pat of butter (or drizzle of oil) and gently toss to prevent the varenyky from sticking together. Continue cooking the remaining varenyky. At the end, add all the remaining fried onions to the bowl and toss to coat.

Step 9

Serve immediately, with sour cream or vegan yogurt. Leftover varenyky are great fried in a pan until crispy.