• Preheat oven to 370℉/180℃. Line a 8″ square baking tin with greaseproof paper. 
• Melt the dark/semi-sweet 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. Alternatively, set up a double boiler. Do this by placing a heatproof bowl over a small pot of simmering water. Add the chocolate to the heatproof bowl and stir until melted. 
• 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 and fold together. Pour the batter into the prepared pan.

For the Cheesecake Layer

• Make the cheesecake layer by whisking the cream cheese, sugar, egg and peanut butter. Pour this over the brownies. Dollop the raspberry jam/jelly over the cheesecake mixture and swirl in using a knife. Finish with a scatter of frozen raspberries if using (about a handful).
• Bake for 33-36 minutes. The cheesecake may look a little wobbly but that is fine! Let cool before slicing and serving!