Classic Weetbix Slice

Thought it was time do something sweet and weetbix slice is so flippen easy! And which New Zealander doesn't have weetbix in their cupboards 😏
Slice:
180 grams of melted butter
1 cap of vanilla essence
3 crushed weetbix
1 cup of dessicated coconut
1 cup of plain flour
1/2 cup of sugar
1/4 Cup Cocoa
(Optional, you can add chocolate buttons, or raisins if you want as well)
Icing:
1 1/2 Cups of Icing Sugar
4 heaped TBSP of Cocoa
100 grams of softened butter
Add hot water to combine