Put the forest fruits in a food processor with the golden syrup and 1 tbsp icing sugar, reserve a handful of fruit to decorate. Whizz together until smooth.
Put one half of a brownie on a plate and top with a spoonful of the berry purée, followed by a small scoop of ice cream. Top with the other brownie half. Repeat with the remaining 3 brownies.
Decorate each plate with a few reserved frozen berries and a spoonful of extra purée. Dust with the remaining icing sugar to serve.