Bryndzové Pirohy (Slovak Bryndza Pierogi)

To make the dough:

1. Place the potatoes in a large pot and cover with cold water. Cover and bring to a boil. Reduce to a low boil and cook until the potatoes are completely tender, 20-30 minutes.
2. Gently remove the tender potatoes from the water and set aside until cool enough to handle.
3. Peel the warm potatoes and press through a potato ricer to make a completely smooth mixture.
4. Set aside 5 ounces (150 grams) of the potatoes for the filling.
5. Place the remaining potato mixture in the bowl of a stand mixer fitted with a dough hook or a large bowl.
6. Add the flour and salt, then combine.
7. Mix in the egg and oil. Slowly pour in the water just until the dough comes together. If too dry and crumbly to bring together, slowly add more water. If too wet and sticky, slowly add a little more flour.
8. On a lightly floured surface, knead the dough until soft and smooth. Wrap in plastic wrap and let sit for at least 1 hour and up to 2 hours.

To make the filling:

1. Combine the set aside 5 ounces (150 grams) mashed potatoes with the bryndza cheese, salt, and pepper. Adjust seasonings as desired and set aside.

To assemble:

1. Line a large baking sheet or counter surface with parchment. Lightly flour a large work surface.
2. Divide the rested dough into 2 equal pieces. Place one piece on work surface and place the other back in the plastic wrap.
3. Roll the dough into a thin sheet, dusting with flour as needed to prevent sticking, until it is about 1/8 inch (3 millimeters) thick.
4. Use a 3 inch (7.5 centimeter) wide circular cutter or the top of a glass to cut out circles of dough. Gather up the scraps and add it to the covered piece of dough.
5. Place a spoonful of the cheese filling to the center of a circle. Fold the circle in half over the filling to make a half moon shape, lightly pressing around the filling to remove any air pockets as you press down to seal the edges. If desired, use a fork to crimp around the edges. Place on prepared parchment in a single layer and repeat with remaining dough and filling.

To serve:

1. In a large pan, place the chopped bacon over medium heat. Cook, stirring occasionally, until crisp and the fat has rendered. Remove from heat and set aside.
2. Bring a large pot of salted water to a boil. Add a few of the Pirohy, taking care not to overcrowd, and stir gently to separate from the bottom.
3. Cook until the Pirohy float to the top and the edges are tender, about 3-5 minutes. Use a slotted spoon to remove, drain, and repeat with remaining Pirohy.
4. Serve the Pirohy immediately with sour cream, the crisp bacon and a drizzle of the rendered fat, and fresh chives.