Preheat your oven to 160 degrees and line a 20cm x 20cm square cake tin with baking paper.
Break the White Chocolate into squares and set aside until needed.
Place the self raising flour, brown sugar, cocoa, coconut and condensed milk into your Thermomix bowl and mix for 10 seconds, speed 4 REVERSE. Scrape down the sides of the bowl and add the white chocolate pieces and mix for a further 10 seconds, speed 4, REVERSE. If your mixture hasn't quite combined, mix for a further 5 - ces
Pour the mixture into your prepared tin (don't worry, it will be VERY sticky!) and smooth the surface with a spoon.
Place the slice into the oven and cook for 20 minutes. Allow the slice to cool completely before cutting into small pieces.
If you want to be extra indulgent, serve this Thermomix White Chocolate Chunk Slice while it is still warm with a scoop of ice cream.