Pierogi

Mix 2 cups flour and 0.5 tsp salt in a large bowl. Create a well, crack in 1 egg, and pour 0.75 cup warm water into the center.

Gradually incorporate flour into the wet ingredients, stirring until a soft dough forms. Knead by hand for 5 minutes until smooth and elastic (dough should be soft but not sticky; add flour or water as needed).

Cover dough with a damp towel and let rest at room temperature for 20 minutes.

Boil 1 lb cubed potatoes in salted water until very tender, about 10 minutes. Drain well and return to pot.

Mash potatoes until smooth. Stir in 0.75 cup cottage cheese, 0.5 cup shredded cheddar, 0.5 medium minced onion, and 0.25 tsp black pepper. Season to taste with salt. Cool slightly.

On a lightly floured surface, roll dough to 1/8-inch thickness. Cut out 24 rounds with a 2-inch cutter (re-roll scraps as needed).

Place 1 tbsp filling on each round, fold in half, and pinch edges firmly to seal.

Bring a large pot of salted water to a boil. Working in batches, add pierogi and stir gently. Once they float, boil 2 minutes more. Remove with a slotted spoon and transfer to a plate.

Heat 2 tbsp butter in a large skillet over medium-high heat. Pan-fry boiled pierogi in batches until edges are crispy and golden, about 2 minutes per side. Transfer to a serving plate.

In the same skillet, melt 1 tbsp butter and add 1 large sliced onion. Cook over medium heat, stirring occasionally, until deeply golden and caramelized, about 12 minutes.

Top pierogi with caramelized onions and serve with sour cream on the side.