PREPARATION:

1. Combine flour, granulated sugar and salt in large bowl; set aside.
2. Cut butter into 1-inch chunks. Add butter and shortening to flour mixture. Cut in with pastry blender or 2 knives until mixture resembles coarse crumbs. Drizzle buttermilk over top; toss just until mixture comes together to form ball.
3. Turn out dough onto lightly floured work surface; fold in half and flatten to about 1/2 inch thick. Knead about eight times. Divide dough in half; press each half into 1/2-inch-thick disc. Wrap in plastic wrap and refrigerate at least 30 minutes.
4. Preheat oven to 350°F. Lightly grease cookie sheets; set aside. Let dough rest at room temperature 10 minutes. Roll 1 dough disc into 18X12-inch rectangle on lightly floured work surface. Cut into 24 (3-inch) squares. Place heaping 1/2 teaspoon mincemeat in center of each square. Fold opposite corners each about 2/3 of the way over filling, overlapping dough corners.
5. Place 2 inches apart on prepared cookie sheets. Repeat with remaining dough.
6. Bake 20 minutes or until lightly browned. Remove cookies to wire racks; cool completely. Sprinkle pastries lightly with powdered sugar, if desired.