Here's the recipe so you might get to love it too.
125 gms of butter
1/2 cup of sugar
1 cup of flour
1 tsp baking powder
2 crushed Weet Bix
2 tbsp cocoa
1/2 tsp vanilla
Mix dry ingredients together. Melt the butter, add vanilla and stir into the dry ingredients with a fork. The mixture is fairly dry. Tip into a tin* lined with baking paper and press the mixture down to fit the pan. Bake at 180 C (350 F) for about 15 mins. Ice with chocolate icing while it's still hot. Leave to cool before cutting into bars or squares.
*I use a square tin 19cm x 19cm.