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 and secure the sides down on the edge of the pan with ¾-inch binder clips.
• Make the brownie batter. Combine chocolate and butter in a saucepan over very low heat and stir constantly until melted and smooth, or melt in the microwave at 50% power in short bursts with frequent stirring.
• Combine eggs, sugar, vanilla and salt in a large bowl and whisk or beat with an electric hand mixer until pale and thick. Whisk in warm melted chocolate mixture until smooth and glossy. Sprinkle flour over the surface and fold it in. Reserve about ⅓ cup (80ml) of brownie batter and spread the rest evenly into the prepared pan.
• Make the cheesecake batter. Beat the soft cream cheese in a medium bowl with an electric hand mixer or spatula until very smooth. Add sugar and vanilla and beat until smooth and glossy. Beat in egg until well incorporated. Spread this batter evenly over the brownie batter in the pan, then spoon teaspoons of the reserved brownie batter randomly over top.
• Make the raspberry swirl. Combine raspberries, sugar and corn starch in a small bowl and mash it up with a fork leaving it just a bit chunky. Spoon teaspoons of this raspberry mixture over the batter in the pan and use a skewer to swirl all of the flavors together.
• Bake for 30-35 minutes until puffed and the cheesecake is set in the middle with lightly golden edges. Transfer pan to a wire rack and let cool completely in the pan. Refrigerate for at least 1 hour before slicing with a hot dry knife.