For the shortbread: Preheat the oven to 375 degrees F. In a food processor fitted with a metal blade, process the all-purpose flour, butter, sugar, cacao nibs, rice flour and cinnamon until it comes together in a rough crumble. Dust some parchment paper with flour and turn the dough out of the work bowl onto the parchment. With a rolling pin, roll the dough out to 1/3-inch thickness. Cut out the cookies with star-shaped cookie cutters and bake until set and just beginning to color at the edges, 10 to 12 minutes. Cool to room temperature before filling.
For the ganache filling: Over a double boiler, melt the chocolate until warm and smooth. Whisk in the cream, stirring until the mixture is velvety. Turn half of the shortbread pieces over. Using a piping bag fitted with a small round tip, pipe 1 teaspoon chocolate ganache onto each piece. Top with another cookie. Allow the sandwich cookies to set until firm. Melt additional chocolate until warm to the touch (84 to 87 degrees F). Drizzle the chocolate over the cookies, or dip the cookies into the melted chocolate. Refrigerate the cookies until the chocolate is set.
This recipe was provided by a chef, restaurant or culinary professional and may have been scaled down from a bulk recipe. The Food Network Kitchens chefs have not tested this recipe, in the proportions indicated, and therefore, we cannot make any representation as to the results.