Preheat oven to 180°C bake. Line a 19 x 19 cm slice tin with baking paper.
Beat the butter, brown sugar, and vanilla essence together until light and fluffy.
Add the flour, oats, coconut, and golden syrup. Mix until well combined.
Press ¾ of the mixture evenly into the prepared tin.
To make the caramel, place the condensed milk, butter, and golden syrup into a saucepan. Heat gently, stirring constantly, until the butter has melted and the mixture is smooth.
Pour the caramel evenly over the base.
Crumble the remaining base mixture over the top of the caramel.
Bake for 30–35 minutes, until lightly golden and the caramel has set.
Allow to cool completely in the tin before slicing.