Preheat the oven to 170°C.

Line a 30x20cm baking tin with foil or baking parchment.

Pop the 280g flour, icing sugar, salt and cubed cool butter in a food processor and pulse until the dough starts coming together in moist clumps OR sift all the dry ingredients for the base together then rub in fridge cold butter with the tips of your fingers. Either way, tip your dough crumbs into your prepared baking tray and flatten with your hand or the base of a glass or measuring cup – it will be less than a 1cm thick at this point.

Bake for 20-25mins or until golden and set, then remove from the oven but leave the heat on as you make the topping.

For the topping, simply whisk together the caster sugar, zest and juice, eggs then sift over the flour and baking powder and stir to combine.

Pour this runny batter over the shortbread base and return to the oven, baking for another 25-30 minutes until the topping has set and has no more than a hint of wibble wobble in the centre.

Leave to go cold in the tin then dredge with icing sugar before slicing and serving.

They keep well in a cool place (aka the fridge if you live in Doha!) in an airtight box for three days ;)