Put the butter, sugar and golden syrup in a large saucepan.
Heat gently, stirring occasionally until butter and sugar have melted. Remove from the heat and mix in the remaining ingredients. Spoon into the prepared tin and press out in an even layer (a potato masher is useful ). Bake for 25 mins until golden around the edges. Cool completely in the tin, then lift our and cut into 12 small bars. Store in the fridge.