Preheat the oven to 350˚F. Line an 8×8 inch pan with parchment paper. Set aside.
Place the prunes and the water in a food processor and process until smooth.
In a large microwave safe bowl, microwave the chocolate and butter in 30 second intervals, mixing until smooth.
Once melted, immediately whisk in the sugar, egg, egg white, prune puree and vanilla until smooth.
In a separate bowl, mix together the flours and cocoa powder. Mix the dry ingredients into the wet ingredients until fully combined.
Pour the batter evenly in the prepared pan. Bake for around 30 minutes, or until a toothpick inserted comes out with a few moist crumbs. Let cool completely in the pan. Using the parchment paper, remove the brownies from the pan, and cut into squares.