Preheat the oven to 180°C~356°F. Then grease and line a baking tray.
In a medium bowl, melt the butter and the dark chocolate. Leave the melted mixture to cool to room temperature.
In a food processor, beat the eggs and the brown sugar until frothy. Then slowly pour the chocolate and the butter mix. Add the vanilla. Transfer the batter into a bowl.
In a separate bowl combine the gluten free flour, baking powder, cocoa powder (leave some for the top) and salt. Mix well, then add to the chocolate mixture. Beat with a spoon until well incorporated.
Chop the white chocolate into chunks and add them into the batter. Stir until they’re dotted throughout.
Pour the mixture into the prepared tin, scraping every bit out of the bowl with the spatula.
Bake for about 25 minutes until cooked when tested with a tooth pick which comes out with a few crumbs. Allow to cool completely. Remove from the baking tin and cut into 12 squares.
Store in an airtight container for up to 10 days and in the freezer for up to a month.
Dust some cocoa powder on the top and garnish with raspberries (or any other fruits - optional).
Enjoy!