Polish Pierogi with Caramelized Onions

Step 1

Pour 1.5 cups flour into a large mixing bowl, make a well in the center with your fingers, and crack the egg into it.

Step 2

Add 0.25 cup water and 0.5 teaspoon salt to the egg, then stir with a wooden spoon, gradually mixing flour from the sides until a shaggy dough forms.

Step 3

Dust your work surface with flour, place the dough on it, and knead by pressing with the heel of your hand, folding the dough back onto itself, and rotating a quarter turn; repeat for 8 minutes until the dough is smooth and elastic, not sticky.

Step 4

Cover the dough with a clean kitchen towel and let it rest at room temperature while you prepare the filling.

Step 5

Place the potato in a small pot, cover with cold water, set the pot on the stove over high heat, and bring to a boil.

Step 6

Reduce the heat to medium and simmer until a fork slides easily through the potato, about 12–15 minutes.

Step 7

Drain the potato in a colander, wait until cool enough to handle, then peel away the skin with your fingers or a small knife.

Step 8

Place the peeled potato in a small bowl and mash it with a fork until completely smooth with no lumps, then set aside.

Step 9

Place the large onion on a cutting board with the root end pointing away from you, slice off the papery skin and root end, then slice the onion lengthwise from top to bottom into thin half-moons, about 1/8 inch thick.

Step 10

Place a 12-inch skillet on the stove over medium heat, add 2 tablespoons butter, and once it melts and foams, add the sliced onion.

Step 11

Stir the onion with a wooden spoon once every 30 seconds, cooking until the edges turn deep golden brown, about 12–15 minutes; if it looks dry, add 1 tablespoon water.

Step 12

Taste a piece—it should be very soft and taste like caramel sugar. Pour the onion onto a plate and set aside.

Step 13

Dust your work surface with flour again, remove the dough from under the towel, and roll it into a flat disk about 1/8 inch thick using a rolling pin.

Step 14

Using a 3-inch round cookie cutter or the rim of a glass, cut circles from the dough; gather scraps, re-roll, and cut more until no dough remains.

Step 15

Place 1 heaping teaspoon of mashed potato in the center of each circle, fold the dough in half to create a half-moon, then press the curved edge firmly with your fingers to seal.

Step 16

Bring a large pot of salted water to a rolling boil over high heat—the water should bubble vigorously and steam should rise steadily.

Step 17

Gently lower the pierogi into the boiling water one at a time using a slotted spoon, wait until all of them float to the surface, then cook for 2 minutes more after the last one floats.

Step 18

Use a slotted spoon to lift each pierogi from the water and transfer it to a plate.

Step 19

Divide the pierogi between two bowls or plates, top with the caramelized onion, add a dollop of sour cream, and serve immediately.