In large bowl, mix together flour and salt. Add butter in small chunks to flour and salt, and use a pastry cutter or fork to cut butter into mixture, like you're making pie dough. Set aside. (Alternatively, you can do this in a food processor, but be careful to not overwork the dough.)
In small bowl, mix together egg yolks, sour cream and wine. Add this mixture to flour/butter mixture. Knead together until just combined.
Flatten dough into disc, wrap in plastic, and place in fridge to chill for one to two hours. Chilling the dough will make it easier to handle.
Once dough is chilled, divide into four equal parts. On lightly floured surface, or parchment paper, roll each piece out as thin as possible, about 1/16". It'll be nearly translucent (it reminded me of wonton wrappers.)
Once thin enough, cut dough into strips that measure about 4" by 1 1/2". Cut a small, diagonal slit into each strip of dough. Pull one end of the strip through the hole, and give it a slight pull (helps keep the dough nice and thin.) Repeat with each strip of dough.
Repeat process with each portion of dough.
Heat frying oil in large pot to 375 degrees Fahrenheit. Set up a cooling rack next to the fryer, and cover it with paper towels to help things stay clean. Working in batches, fry the cheregi until light golden brown. Use slotted spoon to remove fried cheregi, and allow to cool on prepared cooling rack. Keep an eye on the temperature that oil doesn't get too hot during the frying.
Once all cheregi are fried, thoroughly dust them powdered sugar. Keep in air-tight container, if you can manage to not eat them all in one sitting.