01 -
Combine flour and salt in a large bowl. Add the egg and sour cream and mix briefly. Pour in warm water a little at a time, mixing after each addition, until a shaggy dough forms. Turn out onto a lightly floured surface and knead for 6 to 8 minutes until smooth and slightly tacky. Cover with an inverted bowl and rest for 30 minutes.
02 -
Cook ground pork in a dry skillet over medium-high heat, breaking it into fine crumbles, until cooked through with no pink remaining, about 8 minutes. Drain excess fat. Melt butter in the same pan over medium heat and cook the diced onion for 10 to 12 minutes until deeply golden. Combine the pork, onion, and marjoram. Season generously with salt and black pepper. Add broth if the mixture feels dry. Cool completely before using.
03 -
Divide the rested dough in half. Roll one half on a lightly floured surface to about 1/8-inch (3 mm) thick. Cut 3-inch (8 cm) circles using a round cutter or the rim of a glass. Gather and re-roll the scraps once, then repeat with the second half of the dough.
04 -
Place one heaped teaspoon of filling in the center of each circle. Fold the dough over to form a half-moon, keeping the filling away from the edges. Press the edges firmly together from the center outward, then crimp or pleat all the way around to both tips. Check each dumpling for any gaps before cooking.
05 -
Bring a large pot of well-salted water to a boil. Cook pierogi in batches of 10 to 12. They are done about 2 minutes after they float to the surface, 4 to 5 minutes total. Lift out with a slotted spoon and toss with a small knob of butter to prevent sticking.
06 -
In a separate pan, fry the sliced onion in butter over medium heat for 12 to 15 minutes until deeply golden. Melt more butter in a large skillet over medium heat and fry the boiled pierogi 2 to 3 minutes per side until golden and crispy on the outside. Serve topped with the fried onion and sour cream on the side.