1. Beat butter, granulated sugar and vanilla in large bowl until fluffy. Stir together flour, cocoa and salt; gradually add to butter mixture, blending well. Stir in pecans. Cover; refrigerate dough 1 hour or until firm enough to handle.
2. Heat oven to 375°F. Shape scant 1 tablespoon dough into log about 2-1/2 inches long; place on ungreased cookie sheet. Repeat procedure with remaining dough. Shape each log into crescent shape, tapering ends.
3. Bake 13 to 15 minutes or until set. Cool slightly; remove from cookie sheet to wire rack. Cool completely. Roll in powdered sugar. About 3-1/2 dozen cookies.