Pierogi with Potato-Mushroom-Cheese Filling
1 large or 2 medium Yukon Gold potatoes, scrubbed
Kosher salt and freshly y ground black pepper
2 tablespoons unsalted butter
4 ounces sharp white cheddar cheese, coarsely grated
¼ cup freshly grated Parmigiano Reggiano
3 tablespoons canola oil
½ pound cremini mushrooms, stems removed, finely chopped
1 large shallot, finely diced
2 ounces fresh spinach leaves, thinly sliced
2 teaspoons finely chopped fresh thyme leaves
¼ cup chopped fresh flat leaf parsley leaves
1. Preheat oven to 400°. Place the potato on a baking sheet and bake until soft, about 45 minutes. Remove from the oven, let cool slightly, cut in half, and scoop out the flesh into a bowl. Add the butter and cheese and mash until smooth. Season with salt and pepper. Cover and keep warm.
2. In a large sauté pan over high heat, heat the oil until it begins to shimmer. Add the mushrooms and cook, stirring occasionally, until they are golden brown and their liquid has evaporated. Add the shallots, salt, pepper and thyme and cook 5 minutes more. Stir in the spinach and remove from the heat. Add the mushroom mixture to the potato mixture and fold in the parsley. Let cool to room temperature before filling the pierogi. The filling can be made up to 2 days in advance and stored covered in the refrigerator. Remove from the refrigerator 1 hour before using.
2 large egg yolks
¾ cup sour cream
8 tablespoons unsalted butter, at room temperature
1 teaspoon kosher salt
2 cups all-purpose flour, sifted, plus more from rolling
2 eggs, for egg wash
1. In a medium bowl, whisk together yolks, sour cream, butter and salt. Gently mix in the flour until the mixture forms a dough -- be careful not to over-mix. Form into a disc, wrap in plastic and refrigerate for at least 1 hour and up to 2 days.
2. Divide the dough in half. Place one half on a lightly floured surface and return the other half the refrigerator. Roll the dough to 1/8-inch thickness. Use a 3-inch biscuit cutter to cut out circles. Spoon a scant tablespoon of the filling in the center of each round. Lightly brush the bottom half with egg wash, fold the top half over to form a half-moon, and press the edges with a fork to seal. Place the pierogi on a baking sheet lined with parchment and refrigerate for at least 15 minutes. Repeat with the remaining dough and filling.
3. Bring a large pot of salted water to a boil over high heat. Add the pierogi in batches; once they float, cook for exactly 4 minutes. Drain well in a colander.
4. Heat a pat of butter in a sauté pan over medium heat. Once melted and sizzling, add the pierogi and sauté on both sides to lightly crisp the exterior. Season with salt and pepper. Serve the perogi with caramelized onions and a sprinkle of minced parsley.