Potato, Cheddar, and Onion Pierogies

Combine flour and ¾ teaspoon salt in a large bowl. Add eggs, stirring to combine. (Mixture will be dry and shaggy.) Add sour cream and butter, and mix until dough becomes a rough, sticky ball. Knead by hand (avoid adding more liquid or flour) until dough becomes elastic, less sticky, and almost smooth. (Some crevices are fine.) Wrap dough in plastic wrap, and refrigerate for 30 minutes.

Bring potatoes and water to cover by 1 inch to a boil in a medium saucepan. Reduce heat to medium, and cook until potatoes are tender, 10 to 15 minutes.

Heat 2 tablespoons oil in a medium nonstick skillet over medium-high heat. Add garlic and ½ cup onion, and cook until tender, 4 to 5 minutes.

Drain potatoes. To dry, return potatoes to pan, and stir over low heat for 1 to 2 minutes. Using a potato masher, finely mash potatoes. Stir in onion mixture, pepper, and remaining 1½ teaspoons salt. Let cool for 10 minutes; stir in cheese.

Divide dough in half. (Keep one half covered with plastic wrap until ready to use.) On a lightly floured surface, roll half of dough to ⅛-inch thickness. (If dough sticks, add another dusting of flour underneath.) Using a 3-inch round cutter, cut dough, discarding scraps. Place 2 teaspoons filling in center of each circle. Fold dough over filling. Press edges together, and seal with a fork. Repeat with remaining dough and filling.

Fill a large Dutch oven with water, and bring to a boil. Reduce heat to medium. Working in batches of 6 at a time, cook, stirring frequently, until pierogies are tender and float, 2 to 4 minutes. Remove using a slotted spoon.

Coat the bottom of a medium nonstick skillet lightly with oil for each serving. Add boiled pierogies and onion (about 1 tablespoon per serving). Cook, turning occasionally, over medium heat until pierogies and onion are browned, 4 to 5 minutes. Garnish with chives, if desired.