Grease and line tin of choice (see notes for sizes)
Preheat oven to 180 degrees fan forced, and place rack into middle of oven
Place chocolate into TM bowl and mill 10 seconds / speed 9
Add butter and melt mix together 2 minutes / 50 / speed 3
Add light muscovado sugar and mix 5 seconds / speed 4
Add vanilla bean paste and eggs and mix 10 seconds / speed 4
Add flour and salt and mix 1 minute / speed 4 (it is important you mix for the full minute)
Add prunes and chocolate buttons and mix 20 seconds / reverse / speed 1
Pour mixture into tin and spread to the corners
Bake for 25 minutes and then check … when you touch it with your finger in the middle it should still be soft, but if it is very soft bake for a further 2-3 minutes
Remove from oven and allow to rest in the baking tin until cool
Dust with cacao powder before cutting into squares