Preheat oven to 180°C (350°F) standard / 160°C (320°F) fan-forced. Grease and line an 8-inch square pan with baking or parchment paper, ensuring two sides overhang.

In a large mixing bowl, combine icing sugar, plain flour, and desiccated coconut. Whisk to blend thoroughly.

Add melted butter to the dry mixture and stir until it becomes moist; it should have a consistency resembling wet sand.

Press the mixture into the prepared baking pan to form a uniform layer.

Bake in the oven for 12 minutes, or until the edges of the crust are slightly golden. Remove from the oven and set aside while preparing the caramel.

In a medium-sized saucepan, combine sweetened condensed milk, unsalted butter, and syrup (if using). Heat over medium and stir constantly until the butter melts.

Continue cooking, stirring, until the caramel thickens and turns a golden brown, about 10 minutes.

Once thickened, remove from heat and add a pinch of sea salt.

Pour the caramel over the shortbread crust, then bake for another 12 minutes or until the caramel is golden brown on the edges.

Allow to cool for 30 minutes, adding extra sea salt if desired.

Place the chocolate in a microwave-safe bowl and heat until melted, stirring every 30 seconds.

Once melted and smooth, stir in the oil. Carefully pour the chocolate over the caramel layer and spread it evenly.

Chill in the fridge for at least 2 hours to set.

When ready to serve, lift the slice out of the baking tin using the overhanging paper and cut into small squares.

If too hard to cut, let it sit at room temperature for about 10 minutes to soften slightly.