Preparation

• Preheat the oven to 325°F. Line a 9x9-inch square baking pan with parchment paper, leaving a 2-inch overhang at each side.
• Make the brownie batter. Combine chocolate and butter in a saucepan over very low heat until melted and smooth. Alternatively, melt in the microwave at 50% power.
• Combine eggs, sugar, vanilla, and salt in a large bowl and whisk until pale and thick. Whisk in melted chocolate until smooth. Fold in flour and reserve about ⅓ cup of the brownie batter.
• Spread the rest of the brownie batter evenly into the prepared pan.
• Make the cheesecake batter. Beat softened cream cheese in a bowl until smooth. Add sugar and vanilla, then beat until glossy. Beat in egg until well incorporated. Spread this over the brownie batter in the pan.
• Spoon teaspoons of the reserved brownie batter over the cheesecake layer.
• Make the raspberry swirl. Combine raspberries, sugar, and corn starch in a bowl and mash with a fork. Spoon this mixture over the batter and swirl with a skewer.
• Bake for 30-35 minutes until the cheesecake is set and lightly golden at the edges. Let cool completely, then refrigerate for at least 1 hour before slicing.