In a medium bowl, stir together the flour, salt, and sugar. Add the egg, butter and vanilla, mix until dough becomes stiff. Stir in the sherry 1 tablespoon at a time until dough is workable and smooth. Cover and refrigerate for about 2 hours.
On a lightly floured surface, roll the dough out to 1/8 inch thickness. Cut into long narrow strips, and tie into loose knots, do not pull tight. Heat cooking oil to 375 degrees F (190 degrees C). Oil should be about 1 1/2 to 2 inches deep. Fry ties in
hot oil for about 2 minutes, until they puff up and turn golden brown. Drain on a brown paper bag or on paper towels. Dust with confectioners sugar while still warm.