Pierogi Ruskie from Scratch

Ingredients

• 2½ cups flour
• ¾ cup warm water
• 1 egg
• 2 tbsp sour cream, plus more for serving
• 1 lb potatoes, peeled
• 6 oz farmer cheese or twaróg (ricotta works)
• 2 onions, diced
• 5 tbsp butter
• Salt and plenty of black pepper

Method

1. Boil the potatoes until tender, then mash and cool. Meanwhile cook the onions in 3 tbsp butter over medium-low until deeply golden, 15 minutes; fold half into the mash with the cheese, salt, and an aggressive amount of pepper.
2. Knead flour, warm water, egg, sour cream, and ½ tsp salt into a soft, supple dough, about 6 minutes. Rest under a bowl for 20 minutes — resting is what makes it roll thin without fighting back.
3. Roll to ⅛ inch and cut 3-inch rounds. Fill each with a walnut-sized spoonful, fold into a half-moon, and pinch a tight, dimpled seam. Keep finished pierogi under a towel.
4. Simmer in batches in well-salted water; they're done 90 seconds after they bob to the surface. Lift out with a spider.
5. Crisp the boiled pierogi in the remaining butter until blistered and golden on both sides. Serve with the reserved onions and cold sour cream.