Method

• 1.
  Preheat the oven to 200°C.
• 2.
  Place butter and both sugars in the bowl of a stand mixer fitted with a paddle attachment (or use a hand-held electric mixer). Mix on medium speed for 2-3 minutes until light and fluffy. Add egg, vanilla and 1 1/2 tbs water and continue mixing until combined, then blend in the tahini. (You may need to stop the machine and scrape down the sides of the bowl with a spatula a few times to help it combine.)
• 3.
  In a medium bowl, whisk together flour, baking powder, 1/4 tsp salt, oats, orange zest, hazelnuts and sesame seeds. Add the dry ingredients to the stand mixer bowl and mix on low speed until well blended.
• 4.
  Line two baking trays with baking paper. Form 20 rough balls of dough (they should be about 4-5cm wide) and arrange on the prepared trays, about 4cm apart.
• 5.
  Bake for 7-8 minutes, rotating the pans halfway through, and then remove from the oven while the cookies are not quite cooked. Place a piece of halvah in the middle of each cookie and return to the oven for another 4-5 minutes until cookies are golden brown around the edges and the halvah has started to melt. Remove from the oven and set aside to cool for 5 minutes, then transfer to a wire rack to cool completely.
• 6.
  Place chocolate in a medium heatproof bowl and place over a pan of simmering water, taking care that the base of the bowl is not touching the water. Cook chocolate, stirring occasionally, until melted. Remove from the heat and set aside.

• 7.
  Transfer the cookies back to one of the baking sheets so they fit snugly together. Using a teaspoon, drizzle the melted chocolate over the cookies to create thin stripes (or zigzags) all in the same direction. Don’t worry about being exact with this as the cookies should look rustic. Set aside for the chocolate to harden, then serve.