Step 1

Boil the potatoes. Peel 1 1/2 pounds russet potatoes and chop into 1 1/2-inch pieces. Place in a large pot and add enough water to cover the potatoes by 2 inches. Bring to a boil over high heat. Reduce the heat to medium and simmer until the potatoes are tender and can be easily pierced with a paring knife but not falling apart, 11 to 13 minutes. Meanwhile, prepare the bacon and onion.

Step 2

Chop the bacon and onion. Cut 6 slices thick-cut bacon crosswise into 1/2-inch pieces and dice 1 medium yellow onion (about 1 1/2 cups).

Step 3

Drain the potatoes. When the potatoes are ready, drain through a colander and return to the pot. Mash with a potato masher until smooth and no large lumps remain. (Alternatively, pass the potatoes through a ricer or food mill back into the pot.) Let the potatoes cool uncovered until warm but not hot, about 10 minutes.

Step 4

Make the dough. Transfer the potatoes into a large bowl. Wash the pot and fill with water and a generous pinch of kosher salt. Bring to a boil over high heat. Meanwhile, add 2 cups all-purpose flour, 1 large egg, and 1 teaspoon kosher salt to the potatoes. Mix with a wooden spoon or rubber spatula until most of the flour is incorporated and a shaggy dough forms.

Step 5

Knead the dough. Transfer the dough onto a lightly floured work surface. Knead, adding an additional 1 tablespoon of flour if it’s too sticky, until all of the flour is incorporated and the dough is very smooth.

Step 6

Shape the kopytka. Dust the work surface with more flour and divide the dough into 4 portions. Working with one piece at a time, use your hands and roll into a thick rope that’s about 3/4-inch thick. Gently flatten each rope into a thick, rounded belt that's about 1-inch wide.

Step 7

Cut the kopytka. Line a rimmed baking sheet with parchment paper and dust with all-purpose flour. Cut each portion crosswise on a slight diagonal into 1-inch (diamond-shaped) pieces, then transfer them onto the baking sheet in a single layer.

Step 8

Boil the kopytka. Add half the kopytka to the pot of boiling water and stir so they don’t stick together. Boil until they float and are cooked through, 3 to 4 minutes. Use a slotted spoon to transfer to a serving platter. Repeat with the remaining kopytka and loosely cover the platter in foil to keep them warm. Empty and dry the pot.

Step 9

Cook the bacon. Add the bacon to the pot and cook over medium heat, stirring occasionally, until the bacon is browned and crisp, 10 to 15 minutes. Using a slotted spoon, transfer the bacon to a bowl.

Step 10

Cook the onion. Pour the bacon fat into a small heat-proof bowl, then measure out and return 4 tablespoons to the pot. Add the onion and cook over medium heat, stirring frequently, until softened and starting to brown, 7 to 9 minutes.

Step 11

Toss everything together. Turn the heat off. Add the bacon and kopytka to the pot and gently toss to combine. If the kopytka are no longer warm, cook on low heat, stirring often, to reheat, 1 to 2 minutes. Seve immediately with chopped fresh chives and black pepper if desired.