In a large bowl, beat together butter, confectioners’ sugar, salt, and vanilla extract with a mixer at medium speed until creamy, 2 to 3 minutes, stopping to scrape sides of bowl. Gradually add flour, beating until combined. Gently stir in 1 tablespoon crushed raspberries. Shape dough into a disk, and wrap in plastic wrap. Refrigerate until firm, approximately 30 minutes.
Line baking sheets with parchment paper.
Using a rolling pin, roll dough between 2 sheets of parchment paper to a ¼-inch thickness. Remove top sheet of parchment. Using a 1½-inch fluted square cutter, cut as many cookies as possible from dough, rerolling scraps as desired. Place cookies 2 inches apart on prepared baking sheets. Freeze for 30 minutes.
Preheat oven to 400°.
Bake until edges of cookies are lightly browned, approximately 10 minutes. Immediately sprinkle cookies with remaining 1 tablespoon crushed raspberries. Let cool on pans for 10 minutes. Remove from pans, and let cool completely on wire racks.
Recipe by TeaTime Magazine at https://teatimemagazine.com/raspberry-shortbreads/