Note: If you don't want to bake the cookies all at once you can freeze the balls of dough. They can be baked from frozen but will need an additional 1–2 minutes cooking time.
1. Add the butter and sugars to the bowl of a stand mixer, or use an electric hand mixer and large bowl, and beat until light and fluffy, about 5 minutes.
2. Add the eggs, one at a time, beating until fully combined before adding the second. Add the miso and vanilla and mix until evenly combined. In a separate bowl, whisk together the flours, salt, bicarbonate of soda and baking powder.
3. Add the flour mixture to the butter mixture and mix on low speed just until an evenly mixed cookie dough is formed.
4. Add the chocolate and mix briefly, just until evenly distributed.
5. Cover the bowl and refrigerate the dough for 4 hours until firm.
6. Preheat the oven to 180°C/160°C fan and line two large baking trays with baking parchment. Roll into balls weighing roughly 70g each, and place six balls onto each of the prepared trays, spacing them out evenly.
7. Sprinkle each cookie with a little flaked sea salt and bake for 13–15 minutes or until golden around the edges but still a little pale in the centre.
8. Leave to cool on the trays for 5 minutes before transferring to a wire rack to cool completely. Repeat with the second batch of dough balls. Kept covered, these cookies will keep for 3–4 days.
© Matthew Hague
