Shortbread Tombstones

6 tablespoons unsalted butter, softened
5 tablespoons sugar
1/4 teaspoon vanilla extract
1/2 cup all-purpose flour
1/4 cup cornstarch
1/2 ounce bittersweet chocolate, grated

Cream together butter and sugar. Stir in vanilla.

Sift together flour and cornstarch. Stir thoroughly into the creamed mixture. Stir in grated chocolate. Place dough on a sheet of plastic wrap, and form into a flat disk. Wrap the dough, and chill it for at least 2 hours.

Heat the oven to 325�. Line a baking sheet with a Silpat baking mat. Roll out the dough on a lightly floured surface to a 1/8-inch thickness. Trim to a large rectangle. Using a pizza cutter, cut into smaller rectangles, approximately 1 by 2 1/2 inches in size. Chill until firm, about 20 minutes. Bake until firm and just golden, 18 to 20 minutes. Transfer tombstones to a wire rack, and cool.

Makes 25