This recipe for chrusciki was passed down to me from my grandmother. The directions should be followed precisely in order to achieve the perfect crisp and delicate texture. Dust liberally with powdered sugar while the cookies are still warm, and then again once more before serving.
Combine the egg yolks, sugar, almond extract, and lemon zest in the bowl of a stand mixer. Using the paddle attachment, beat at medium until the eggs are thick and bright yellow. The consistency will be just a bit thinner than pudding.
Reduce the speed to low, add the sour cream, and beat until throughly mixed, about 1 minute.
Keeping the speed at the lowest setting, add the sifted flour one heaping tablespoon at a time. Allow the flour to be fully worked into the dough before adding the next batch.
Turn the dough out onto a floured surface. It will be dry and a little crumbly. Knead 10-12 times, then cover with a tea towel and rest for 1 hour.
Divide the dough ball into 8 pieces, then divide each piece in half. Remove one piece of dough, and cover the rest with the towel.
Roll out the dough into a large circle until paper thin. Using a pastry wheel, slice the dough into 5" x 2" strips. Make a small slit in one end of the dough, then pass the other end of the strip through the opening to create a knot. Set the raw dough aside onto a baking sheet. Repeat this process with the remaining portions of dough.
Heat the vegetable oil in a dutch oven to 370°F. While the oil is heating up, prepare several plates or baking sheets lined with paper towels.
Add 3-4 raw chrusciki to the oil and fry, turning once using forks or tongs, until puffed up and golden brown, about 30 seconds per side. Remove the chrusciki from the oil using a slotted spoon, drain on the paper towel lined plates, and then dust with powdered sugar while still warm. Repeat with the remaining cookies. Watch the temperature of the oil and ensure it stays within 5 degrees of 370° throughout the deep frying process, adjusting the heat level as necessary.
Chrusciki are best the day-of, but can be kept up to 2 days. To store, lay flat on baking sheets and cover loosely with aluminum foil. Dust again with powdered sugar just before serving.