Preheat oven to 350°F (175°C). Line a 9x9-inch baking pan with parchment paper, leaving an overhang.

In a bowl, cream 1 cup softened butter and granulated sugar until pale. Gradually mix in the flour and salt until a crumbly dough forms.

Press the dough evenly into the prepared pan. Prick all over with a fork. Bake for 20-25 minutes until light golden brown. Let cool completely.

In a heavy saucepan, combine 1 cup butter, brown sugar, golden syrup, and condensed milk over medium-low heat until melted and smooth.

Bring to a gentle boil over medium heat, stirring constantly. Reduce heat to medium-low and boil, stirring continuously, for 5-7 minutes until thickened.

Remove from heat, stir in vanilla and sea salt. Pour immediately over the cooled shortbread base. Let set for 1 hour at room temp or 30 mins in the fridge.

Melt the chopped chocolate and coconut oil in the microwave in 30-second increments, stirring until smooth.

Pour the melted chocolate over the set caramel and spread evenly. Chill in the refrigerator for 1-2 hours until set.

Let sit at room temperature for 10 minutes before slicing. Use a hot, dry knife for clean cuts.