1 cup (136 grams) flour
¼ cup (21 grams) cocoa powder
113 grams butter, cut into chunks, at room temperature
⅓ cup (67 grams) sugar
1 cup (200 grams) sugar
2 Tbsp water
1 Tbsp light corn syrup
½ cup (120 ml) fresh cream, at room temperature (or slightly warmed in a microwave)
2 Tbsp (1 ounce; 28 grams) butter, cut into 3 pieces and very soft
2 ounces (57 grams) dark chocolate, finely chopped
About ½ cup (60 grams) pecans, toasted and coarsely chopped
Center a rack in the oven and preheat it to 180 degrees Celsius. Generously butter (or spray) an 8-inch square pan.
Whisk together the flour and cocoa powder.
Beat the butter and sugar together on medium speed until smooth, about 2 minutes.
Turn off the mixer, add the dry ingredients all at once and beat on low until the dough comes together. This will take a little longer than you might expect, so don’t get discouraged. Give the dough a few last turns with a flexible spatula and scrape it out into the pan. Using your fingertips, pat the dough evenly over the bottom of the pan; press down and make sure to get the dough into the corners.
Bake the shortbread for 21 to 23 minutes, rotating the pan after 10 minutes, or until it is slightly darker around the edges and just starting to pull away from the sides of the pan; it will not feel completely firm if poked gently. Transfer the pan to a rack and allow the shortbread to cool completely.
Put the sugar, water and corn syrup in a small saucepan and bring to a boil over medium-high heat. Allow the ingredients to bubble away, brushing down the sides of the pan with cold water if there are spatters and swirling the pan a couple of times once you start seeing some color, until the caramel turns a pale to medium amber. (Don’t let it get as dark as mahogany.)
Lower the heat, stand away from the pan and add the cream, followed by the butter. Remove the pan from the heat, drop in the chocolate and stir to blend.
Pour the hot caramel over the shortbread and sprinkle with the nuts. Allow to set at room temperature.
When the caramel is firm, run a table knife around the sides of the pan, carefully unmold onto a rack and turn it over onto a cutting board. Using a long thin knife, cut into bars.
Store in the refrigerator to retain crispness.