These rich, delicate, apricot-filled cookies are in the tradition of rugelach and other rolled-up pastries.
Mix flour, salt, and sugar. With a pastry blender, cut butter into flour until mixture resembles coarse crumbs. Stir in sour cream and egg. Knead lightly until mixture holds together. Wrap well in plastic wrap and refrigerate for 4 hours or overnight.
Divide dough into thirds. On a lightly floured pastry cloth, roll each third into a circle 11 inches in diameter. Spread each circle evenly with 2 tablespoons apricot preserves and 2 tablespoons ground walnuts. Cut each circle into 12 pie-shaped wedges. Roll up each wedge, starting at the wide end. Place seam side down, about 2 inches apart, onto greased cookie sheets. Bake at 375 degrees F for 20 minutes, or until golden brown. Place onto wire rack to cool. Dust with confectioners’ sugar when completely cool.