HUNGARIAN PLUM DUMPLINGS

Steps:

• Cook potatoes for dough:
• Cover potatoes with salted cold water (1 tablespoon salt for 2 quarts water) in a large saucepan and simmer until tender, about 40 minutes. Drain potatoes and, when cool enough to handle, peel. Force warm potatoes through ricer into a shallow baking pan and spread out to cool completely.
• Make crumb mixture while potatoes cook:
• Heat 2 tablespoons butter in a 12-inch nonstick skillet over medium heat until foam subsides, then cook bread crumbs and walnuts, stirring frequently, until crumbs are golden and crisp, about 5 minutes. Cool completely. Transfer to a bowl, then stir in 1/4 cup sugar and 1/2 teaspoon cinnamon.
• Make dough:
• Transfer cooled potatoes to a bowl and stir in flour, salt, softened butter, and yolks until a dough forms. Knead on a well-floured surface just until smooth, about 1 minute (dough will be soft). Cut dough in half and let stand, uncovered, 15 minutes. Roll out half of dough on floured surface with a floured rolling pin into a 10-inch round (1/8 inch thick) and cut out 6 rounds with cutter, reserving scraps.
• Make filling and assemble dumplings:
• Melt 1 1/2 tablespoons butter, then stir together with plums and remaining 3 tablespoons sugar and 1/4 teaspoon cinnamon in a small bowl.
• Place 1 dough round in center of your hand. Put 1 tablespoon filling in center of round, then fold round in half, forming a semicircle, and pinch edges to seal. Gently form into a ball and gently roll between your palms until smooth. Transfer dumpling to a wax-paper-lined tray. Repeat with remaining 5 dough rounds, then make more dumplings with remaining dough, rerolling scraps.
• Cook and coat dumplings:
• Cook dumplings in a pasta pot of boiling lightly salted water (1 tablespoon salt for 5 quarts water) and simmer, uncovered, until dough is firm to the touch, about 12 minutes. While dumplings cook, melt remaining 4 1/2 tablespoons butter in cleaned 12-inch nonstick skillet over medium-low heat. Gently transfer cooked dumplings with a slotted spoon to skillet, spooning butter over them to coat. Transfer dumplings to a platter and sprinkle with half of crumb mixture. Serve immediately, with remaining crumb mixture on the side.