Preheat the oven to 200 degrees C
Line a 20cm square tin with baking paper, making sure that the paper rises up over the edges of the tin
For the shortbread, sift the icing sugar and cornflour into the bowl of an electric mixer with the paddle attachment in place, then add the caster sugar and mix on a medium speed
With the machine still running, slowly pour in the melted-but-cooled butter and beat until combined Add the vanilla and reduce the speed to low, then sift in the flour and salt and continue to beat until the dough comes together
Tip the mixture into the tin and use your hands to pat and even out the surface
Bake for 25 minutes or until golden brown
Remove from the oven and set aside until completely cool: this will take an hour or so, so don’t start making the caramel too soon or it will have set by the time the shortbread is cool
For the halva layer, place the halva and tahini in a small bowl and mix with a wooden spoon to combine
Spread the mix over the cooled shortbread and use the back of a spoon to smooth it out to an even layer
To make the caramel, place the sugar and water into a small saucepan and place over a medium-low heat
Stir occasionally, until the sugar has dissolved, then increase the heat to medium-high
Bring to a boil and cook – still at a boil – for about 12 minutes, until the sugar is a deep golden brown
Remove from the heat and add the butter and cream: take care here, as the mixture will splutter Whisk to combine and, once the butter has melted, add the tahini and salt
Whisk to combine again, then pour evenly over the halva layer in the tin, so that all of the halva is covered
Place in the fridge for at least 4 hours until set, before cutting into 16 bars
Sprinkle a pinch of sea salt over the middle of each bar and serve
Tips:
The shortbread layer can be made up to 4 days in advance and stored in an airtight container. It also freezes well.
These will keep for up to 1 week in an airtight container in the fridge. Remove them from the fridge 20 minutes before serving, to take off the chill.
Recipe from Sweet by Yotam Ottolenghi and Helen Goh