Pierogi with Potato and Cheese

Peel and cut the Yukon Gold potatoes, finely dice the yellow onion, and grate the sharp cheddar cheese before starting the filling.

Place the potatoes in a large pot, cover with water, add 1 teaspoon fine sea salt, and boil until fork-tender, 12 to 15 minutes. Drain well, return to the pot, and mash until smooth.

Melt 2 tablespoons unsalted butter in a skillet over medium heat, add the onion, and cook until soft and golden, 8 to 10 minutes. Stir the onion, cheddar, 1 teaspoon fine sea salt, and black pepper into the potatoes, then cool the filling until no longer hot.

In a large bowl, mix 4 cups all-purpose flour with 1/2 teaspoon fine sea salt. Stir in the egg, warm water, and 2 tablespoons melted unsalted butter until a shaggy dough forms, then knead for 5 to 7 minutes until smooth.

Cover the dough with a clean towel and let it rest for 30 minutes. Divide the dough in half, keeping one half covered while you roll the other half on a surface dusted with some of the remaining 1/2 cup flour to about 1/8 inch thick.

Cut dough rounds with the cutter, place 1 tablespoon potato-cheese filling in the center of each round, and pinch the edges tightly to seal. Gather and reroll scraps as needed. Repeat with the remaining dough and filling, keeping shaped pierogi covered with the towel on a lightly floured tray. You should have about 48 to 52 pierogi.

Bring a large pot of water to a gentle boil and add the remaining 1 1/2 teaspoons fine sea salt. Boil pierogi in batches, stirring gently once to prevent sticking, until they float to the surface, then cook 2 minutes longer.

Lift the pierogi out with a slotted spoon and transfer to a bowl. Toss with the remaining 2 tablespoons melted unsalted butter and serve warm and tender.