Preparation Sift flour, baking powder, and salt into medium bowl. Using electric mixer, beat butter in large bowl until smooth. Add sugar and beat until blended. Beat in egg and vanilla. Add flour mixture and beat until moist clumps form. Gather dough into ball. Flatten and shape into rectangle. Wrap in plastic and refrigerate until cold, at least 1 hour. (Can be made 1 day ahead. Keep refrigerated. Soften dough slightly before rolling out.) Roll out dough on lightly floured surface to 13x10-inch rectangle (about 1/4 inch thick). Mix jam and coconut in small bowl to blend. Spread over dough, leaving 1/2-inch plain border. Sprinkle nuts evenly over jam mixture. Starting at one long side, roll up dough jellyroll style into 13x2 1/2-inch log. Wrap in plastic and chill 30 minutes. Preheat oven to 375°F. Line 2 baking sheets with parchment paper. Unwrap cookie log; cut 1/2 inch off each end and discard. Cut remaining log crosswise into 1/2-inch-thick rounds. Arrange rounds, cut side down, on prepared sheets, spacing 1 inch apart; reshape into neat rounds, if desired. Bake cookies until edges and bottom are golden, about 20 minutes. Transfer cookies to racks and cool.
Preparation Sift flour, baking powder, and salt into medium bowl. Using electric mixer, beat butter in large bowl until smooth. Add sugar and beat until blended. Beat in egg and vanilla. Add flour mixture and beat until moist clumps form. Gather dough into ball. Flatten and shape into rectangle. Wrap in plastic and refrigerate until cold, at least 1 hour. (Can be made 1 day ahead. Keep refrigerated. Soften dough slightly before rolling out.) Roll out dough on lightly floured surface to 13x10-inch rectangle (about 1/4 inch thick). Mix jam and coconut in small bowl to blend. Spread over dough, leaving 1/2-inch plain border. Sprinkle nuts evenly over jam mixture. Starting at one long side, roll up dough jellyroll style into 13x2 1/2-inch log. Wrap in plastic and chill 30 minutes. Preheat oven to 375°F. Line 2 baking sheets with parchment paper. Unwrap cookie log; cut 1/2 inch off each end and discard. Cut remaining log crosswise into 1/2-inch-thick rounds. Arrange rounds, cut side down, on prepared sheets, spacing 1 inch apart; reshape into neat rounds, if desired. Bake cookies until edges and bottom are golden, about 20 minutes. Transfer cookies to racks and cool.