Beat butter, sugar, yolks, vanilla and salt until fluffy. Add almonds and 1-2/3 cups of the flour. Blend on low speed just until combined. Stir in remaining flour by hand. Divide dough into 4 equal pieces; wrap in plastic. Refrigerate at least one hour or overnight.
Heat oven to 375 degrees F. Lightly grease baking sheets. Roll one-fourth of dough into 12-inch rope. Cut into twelve 1-inch lengths. Shape each into 3-inch logs, tapering ends to points. Bend into crescents; place 1 inch apart on prepared sheets.
Bake at 375 degrees F for 12 to 15 minutes until very lightly golden. Set on racks until cool enough to handle but still very warm.
Place confectioners sugar in medium-size bowl. Carefully roll warm cookies in sugar to coat. Set on racks; sift remaining sugar over cookies. Let cool. Makes 4 dozen crescents.