Preheat the oven to 180°C. Line a 23cmx33cm brownie pan with parchment paper, leaving roughly a 5cm overhang, to help remove the brownies later.
Sift the flour, cocoa powder and salt together into a bowl and set aside. In a medium pan set over medium heat melt the chocolate and butter together. Once fully melted whisk in the sugars, then remove from the heat. Firmly whisk in the eggs and vanilla until the eggs are combined and the batter has thickened slightly. Add the flour mixture and gently fold together. You want to fold it in completely, a few spots of flour is fine. Pour into the prepared pan and gently level out.
For the topping beat all the ingredients, except the raspberries together until smooth. Place spoonfuls of the batter on top of the brownie base and use a knife to gently swirl together. Sprinkle the raspberries across the brownies. Bake in the preheated oven for 35-40 minutes or untila toothpick inserted into the middle comes out with just a few moist crumbs. Cool in the pan before cutting into squares.
Recipe courtesy of Edd Kimber.