Cream the butter and sugar together until fluffy. Add eggs and egg yolks one by one while continuing to beat, then add salt, whiskey, and vanilla. Stir in flour until a smooth dough is formed. Cover, and refrigerate for 1 hour.
Roll out dough on a well floured surface until very thin, about 1/8-inch thick. Cut dough into rectangles measuring 1x4 inches. Grasping each end of a dough strip, give it two twists to form a bowtie shape. Repeat with remaining dough.
Heat oil in a deep-fat fryer to 375 degrees F (190 degrees C).
Fry the cookies in batches until golden brown on both sides, turn them over half way through so they cook evenly. Drain cookies on a paper towel-lined plate, then dust with powdered sugar.