225g unsalted butter at room temperature
95g icing sugar
1 large egg yolk
2 teaspoons vanilla extract
⅛ teaspoon fine sea salt
320g all-purpose flour
65g cocoa nibs
2 ounces 70% chocolate, chopped
¼ teaspoon coconut oil
Flaky sea salt
In the bowl of an electric mixer fitted with the paddle attachment or beaters, beat together butter and confectioners’ sugar until smooth and fluffy. Beat in egg yolk, vanilla and fine sea salt until combined. Beat in flour and just as it’s coming together, add in the cocoa nibs. Beat only until everything is combined.
Shape dough into a 1-inch-thick disk, and chill for at least 1 hour and up to 3 days. You can also skip this step and go straight to the next if you are planning to cook your biscuits the same day.
Between two sheets of parchment paper, roll dough until it’s 1/4-inch thick, then chill the dough for at least 30 minutes or until firm.
Position racks in the top and bottom thirds of the oven, and heat oven to 160° C. Line 2 baking sheets with parchment paper.
Use a 2-inch round cutter to cut out biscuits, and transfer to lined sheets. Re-roll and cut scraps.
Bake the biscuits until they are puffed and deeply golden, 18 to 25 minutes, rotating and switching the baking sheets halfway through. Cool on the baking sheets for 5 minutes, then use a spatula to transfer them to wire racks to finish cooling completely.
Place chocolate in a small bowl with the coconut oil. Melt the chocolate in the microwave in 30-second bursts, stirring after each burst. Alternatively, place the bowl over a pot of simmering water, and stir until chocolate is smooth and melted.
Using a fork, drizzle the chocolate over the cooled cookies. Sprinkle with flaky sea salt while the chocolate is still melted. Let set for at least an hour or two before serving. Or store in an airtight container, between layers of parchment or wax paper, for up to 3 days.