1950's choc n’ roll slice - Weet-Bix

Ingredients

• 5 Weet-Bix crushed
• 1½ cups plain flour
• 2 tsp baking powder
• 2 tbsp cocoa
• ¾ cup dessicated coconut
• 1 cup sugar
• 1 tbsp golden syrup
• 200g margarine
• 1 tsp vanilla essence
• 2 cups icing sugar, sifted
• 1 tbsp margarine