How to Make It
Preheat the oven to 350°. Butter a large rimmed baking sheet. In a medium bowl, stir the all-purpose and pecan flours with the sugar, cinnamon and salt. Using a pastry cutter or your fingers, cut in the butter until the mixture resembles fine cornmeal. Add the egg yolk and blend it in with a fork. Lightly knead the shortbread dough until it is smooth.
Transfer the shortbread dough to the prepared baking sheet and flatten it into a 6-inch round. Refrigerate the dough until it is well chilled, about 20 minutes.
Using the blunt side of a knife, score the dough into 8 wedges. Lightly press a pecan into the wide end of each wedge. Bake for about 35 minutes, until the shortbread is browned around the edge. While the shortbread is still warm, cut it into wedges with a serrated knife. Let the shortbread cool to room temperature, then drizzle with the chocolate and serve.