Method:

1. In a small bowl, melt the semisweet chocolate into your microwave oven in 10 seconds increments, stir with a spoon on each pause, don’t burn your chocolate, mix in the sifted cocoa powder, set aside to cool

2. In the bowl of your stand mixer fitted with the paddle attachment, beat the butter and sugar on high speed until light and fluffy, about 3 to 4 minutes, beat in the egg and vanilla extract

3. In a separate bowl, whisk together the flour, salt and baking powder, add to the butter mixture, beat in on low speed just until all incorporated, don’t overbeat

4. Remove half of the dough, about 9 oz. (255 g.), add the chocolate mixture to one half of dough, incorporate with a spatula

5. Form 8 balls of dough out of each half, press together chocolate and vanilla balls alternately, shape into a round log of about 12 inches long (30 cm), 1.75 inches diameter (4.5 cm), wrap into plastic wrap and freeze for about 15 minutes, roll your log every 5 minutes to re-shape the bottom layer

6. Preheat your oven to 180°C, line a baking sheet with parchment paper, slice the log into 1/3 inch thick (1 cm) cookies, place them on the prepared baking sheet spacing them about 2 inches apart.

7. Bake for 10 minutes or until the edges are firm to the touch and slightly golden, place the baking sheet on a cooling rack to cool at least 10 minutes, don’t touch the cookies right out of the oven as they will be very soft and fragile

These cookies will keep for up to a week stored into a cookie box or lidded plastic container