Preheat the oven to 180ºC and line a 20cm x 20cm pan with baking paper.
Place the butter, honey and coconut oil into a small saucepan and heat over medium heat and simmer for 1 minute.
Meanwhile, place the weetbix/weetbix bites, flour, baking powder, chia seeds, cocoa and coconut into a large bowl and mix to combine. Add the honey mixture and the vanilla and mix well to combine.
Press into lined baking tray, smooth out and bake for 15 minutes. Remove from the oven and allow to cool.
Place all ingredients for the icing into a small bowl and mix well to combine. Pour over the top of the slice and spread to the edges. Sprinkle with desiccated coconut.
Cut into pieces and refrigerate for up to 5 days.
