Varenyky ( dumplings) with potatoes and mushrooms

Description

Varenyky are made from fresh dough and potatoes and mushrooms fillings.

Recipe

Start the dough. Combine 1 egg, 2/3 cup water, and 1/2 teaspoon salt in a large bowl, and whisk to incorporate the egg into the water. Add 1 cup flour, mix lightly to incorporate, then add 1 1/4 cups more flour. Combine into a shaggy dough.
Knead the dough. Turn the dough out onto a floured surface. Knead with the heels of your palms – giving the dough a quarter turn every now and then – for about 5 minutes, incorporating the remaining 1/4 cup flour as needed. The dough is done when it’s smooth, elastic, and no longer sticks to your hands. Place the dough back in the bowl, cover loosely with a kitchen towel, and rest for 30 to 60 minutes at room temp.

Meanwhile, start the filling. Place the potatoes in a pot with 1 teaspoon salt and enough water to cover by about 2 inches. 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, 12 to 15 minutes

Meanwhile, heat 2 tablespoons 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.

Finish the filling. Drain the potatoes and return to the pot. Mash until smooth. Stir in about a third of the fried onions with their oil. Season to taste with salt and pepper. Cool the mixture to room temp. Chop the mushrooms and fry in a pan with olive oil, add to the potatoes
Roll out the dough. Divide the dough into 4 pieces. Working with 1 piece at a time (keeping the remaining dough covered with the towel), roll the dough between your palms into a 1-inch-thick log. On a floured surface, cut the log into 8 to 10 1-inch pieces. Using a rolling pin dusted with flour, roll out each piece into an approximately 3-inch circle; if the dough is sticking to the surface or rolling pin, dust it with more flour.
Bring a large pot of water to a boil and salt it generously. 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 has returned to a simmer, and they’ve simmered for about 1 minute. Do not overcook, as the filling may escape the dough
Using a small mesh strainer or slotted spoon, fish the varenyky out and place in a large bowl. Immediately add a small pat of butter (or drizzle of oil) and gently toss to prevent the varenyky from sticking together.
Serve immediatly, alongside sour cream.