Preheat oven to 200C/180C Fan/Gas 6. Line a 8″ square baking tin with greaseproof paper.
Melt the dark chocolate by breaking up into small pieces in a bowl and heating for 30 second intervals in a microwave, stirring in between. Set aside to cool whilst making the brownies.
In a large bowl or the bowl of a stand mixer combine the melted butter, and both the brown and granulated sugars on a medium speed until totally combined.
Add the eggs and vanilla and mix again. Then check that the chocolate has cooled a little before adding in and combining.
Add in the flour, cocoa powder, frozen berries, milk chocolate and fold together. Reserve about 1/4 cup of the batter, pouring the rest into the prepared tin.
Make the cheesecake layer by combining all ingredients in a small bowl and mixing with a spoon.
Pour this cheesecake mixture over the brownie layer. Then, mix together that reserved brownie batter with a little water to thin it out (about 50ml) and drizzle over the cheesecake. Swirl to make a nice pattern!
Squish the raspberries using a fork and drizzle over the batter.
Bake for 35-40 minutes. It will look puffy and should not wobble much at all. Let cool on a wire rack. Once completely cooled, slice and serve!
