Make the sauce by placing the butter, sugar, golden syrup and vanilla in a saucepan. Bring to the boil over a medium heat, stirring continuously.
Add the cream and salt and boil for 5 minutes, stirring occasionally, until thickened. Remove from the heat and transfer to a jug.
Divide the chocolate brownies between 4 bowls and top each with a scoop of ice cream. Pour over the salted caramel sauce and serve immediately.