|Potatoes||4 Medium, peeled and quartered|
|Milk||1⁄3 Cup (5.33 tbs)|
|Chopped green onion||2 Tablespoon|
|Salt||1 Teaspoon, divided|
|Ground white pepper||1⁄2 Teaspoon, divided|
|All purpose flour||2 3⁄4 Cup (44 tbs)|
|Sour cream||1 Cup (16 tbs)|
|Vegetable oil||1 Tablespoon|
To prepare filling, place potatoes in medium saucepan; cover with water.
Bring to a boil over high heat.
Reduce heat to medium.
Simmer, uncovered, 20 minutes or until tender.
Drain; return potatoes to saucepan.
Mash potatoes with potato masher.
Stir in milk, butter, green onion, 1/2 teaspoon salt and 1/4 teaspoon pepper.
To prepare pierogi dough, combine flour, sour cream, egg, egg yolk, oil, and remaining 1/2 teaspoon salt and 1/4 teaspoon pepper in medium bowl; mix well.
Turn out dough onto lightly floured surface.
Knead dough 3 to 5 minutes or until soft and pliable, but not sticky.
Let rest, covered, 10 minutes.
Divide dough in half.
Roll out each half into 13-inch-diameter circle on lightly floured surface with lightly floured rolling pin.
Cut out dough with 2 1/2-inch-round cutter.
Place 1 rounded teaspoon potato filling in center of each dough circle.
Moisten edges of circles with water and fold in half; press edges firmly to seal.
Bring 4 quarts lightly salted water in Dutch oven to a boil over high heat.
Cook pierogi in batches 10 minutes.
Remove with slotted spoon to serving dish.
Garnish, if desired.