Combine all ingredients in a medium-sized bowl and whisk until thoroughly combined; set aside.

Combine the flour and sour cream in your mixer's bowl; mix with the dough hook until you have a soft ball of dough. If too wet, add a tablespoon of flour, if too dry, add more sour cream, one tablespoon at a time.

Lightly flour your working table and turn out the dough.

Roll out the dough to a 1/4-inch thickness.

Use several passes to roll it to the desired thickness. Don't try to flatten it all the way with just one pass.

Using a 3-inch round cookie cutter, cut dough into 20 rounds, rerolling the scraps as needed.

Place filling into center and fold in half, closing edges with tines of fork. Be sure all edges are sealed.

Heat oil.

Place 2 to 3 pierogies in the hot oil and cook for 2 minutes, or until the pierogies float to the top and the edges start to brown; flip and cook for another minute or two, or until completely browned.

Remove and drain on paper towels.

Repeat until you have used up all the pierogies.

Serve plain or with a side of sour cream, melted cheese, or salsa.