Pierogies are a traditional Polish dish. It isn't difficult to make and can be filled with many things. These pierogies are filled with mashed potatoes. What a great way to used leftover mashed potatoes!
2 c. all-purpose flour, plus more for dusting
3/4 c. milk
1/4 t. Kosher salt, plus more to salt the water
2 c. mashed potatoes
1 stick butter
1 small onion, chopped
sour cream and chopped parsley, for serving
Combine flour, milk and 1/4 t. salt in a food processor; pulse until dough forms into a ball.
Roll out dough on a floured board; cut into 2 1/2 x 2 1/2 in. squares. Drop 2 t. mashed potatoes in center of a dough square. Dip a finger in water, run it around the edge of the square, fold potato inside and pinch the edges to seal. Repeat with the remaining dough and potato filling. Place the finished pierogies onto floured sheet pans.
Bring a large pot of salted water to a rolling boil; drop in the pierogies. When they all float to the top, they are done, 3 - 4 minutes. Strain; place in a bowl.
While pierogies are cooking, in large skillet over medium heat, melt butter. Add onions and saute until medium brown, 6 - 8 minutes. Pour over the pierogies, gently toss and serve.
Can also be served with a dollop of sour cream and chopped parsley, for garnish.