Ingredients
DOUGH:4 cups all-purpose flour2 large eggs, room temperature1/2 cup sour cream1 teaspoon salt2/3 cup warm waterPOTATO FILLING:1/2 pound potatoes, peeled, cooked, drained and mashed, about 2 medium1/4 medium onion, chopped2 tablespoons butter, softened1/4 teaspoon salt1/4 teaspoon pepperCHEESE FILLING:1 cup 4% cottage cheese, drained and patted dry1 large egg yolk, beaten 1/4 teaspoon salt2 tablespoons butter, meltedCOOKING LIQUID:3 chicken bouillon cubes8 cups water1 teaspoon canola oilTOPPING:1/2 cup butter1 large onion, chopped2 cups sliced mushrooms
Preparation
To make dough, mix flour, eggs, sour cream, salt and water (a little at a time). Knead dough until firm and elastic; cover and let rest 10 minutes.
For potato filling, combine ingredients; set aside. For cheese filling, combine ingredients; set aside.
Divide dough into 3 parts. On floured surface, roll dough to 1/8-in. thickness; cut into 3-in. rounds with cutter, rerolling dough as needed. Place 1 teaspoon filling in center of each round; fold and press edges together firmly to seal.
Dissolve bouillon cubes in water in large saucepan; add oil. Heat to a simmer over medium heat. Working in batches, drop pierogi into simmering water. Do not crowd. Simmer until tender, about 15 minutes, stirring gently with wooden spoon to prevent sticking. Remove with slotted spoon; drain well.
Melt butter in a large skillet over medium heat; add onion. Cook until lightly browned, 2-3 minutes. Add mushrooms; cook until tender, stirring occasionally, about 5 minutes. Place drained pierogi on serving platter. Top evenly with mushroom mixture.
