In a bowl, whisk mayo, oil, salt, water, and milk. Sprinkle yeast over top of mixture and sprinkle sugar over yeast, let sit 3-5 minutes to activate. (Cover bowl so water stays warm.)
Gradually add flour, mix until flour is well incorporated and combined. Cover with plastic wrap and a kitchen towel. Set dough aside to rise 1 ½ to 2 hours until the dough doubles, almost triples in size.
Prepare filling-
Peel and cut potatoes into even pieces. Place potatoes in a pot and cover with water, sprinkle the salt. Bring potatoes to a boil and cook until potatoes are easily pierced with a fork.
Meanwhile, sauté onion with butter on medium heat.
Once potatoes are cooked, drain water, set potatoes aside to cool a few minutes.
With a mixer (or masher), mash potatoes. Add sautéed onions/butter, sour cream, cheese, herbs, and mix. Taste filling. Add additional salt if necessary.
Assemble Piroshki-
Divide dough into two. Take one half and divide into two again. Then take that half and cut into 2-3 pieces.
Roll out each piece of dough. Add a generous portion of potato filling. Tightly seal edges and turn over with the sealed side on the bottom. Repeat with remaining dough and filling.
Brush piroshki with egg wash. Set aside to rise another ½ hour.
Baked 18-22 minutes, until really golden in color. Enjoy!
Notes
*To get the water and milk warm, I just combine the two in a small saucepan on the stove top and get it nice and warm. Not a fan of the microwave. **You can use whatever cheese you have on hand. For this recipe I used a combination of shredded Mozzarella and Colby Jack cheese. Four cheese is wonderful and even Mexican style.If you bake these, we’d love to see your creation on Social Media. Tag us #ValentinasCorner.