Heat oven to 165 degrees C

Line a 20cm x 20cm baking pan with enough baking paper to hang over two of the sides (to be used as handles later to lift the bars out of the pan)

Pulse together the flour, sugar, icing sugar and salt in a food processor, or whisk together in a large bowl

Add the butter and pulse (or use two knives or your fingers) to cut the butter into the flour until a crumbly dough forms

Press dough into prepared pan and bake until shortbread is pale golden all over, 30 to 35 minutes.

While the shortbread is baking, prepare the passion fruit curd

In a small saucepan, whisk together passion fruit pulp, lemon juice, sugar, eggs and yolks, cornstarch and sea salt over medium heat until boiling and thickened (about 3 to 5 minutes)

Make sure mixture comes to a good boil for one minute (but not longer) or the cornstarch won’t activate and the curd will be thin and runny

Remove from heat and whisk in butter and olive oil

When the shortbread is ready, take it out of the oven and carefully pour the curd onto the shortbread base

Allow to cool to room temperature, then refrigerate until cold before cutting into bars

Sprinkle with icing sugar (optional)