Preparation

• Adjust the oven rack to the lower-third position and preheat the oven to 350°F (177°C). Line the bottom and sides of a 9-inch square or 11×7-inch baking pan with parchment paper, leaving an overhang on the sides to easily lift the cooled brownies out of the pan.
• Make the brownie batter: Melt the butter and whisk in oil and sugar, let sit, then whisk in eggs and vanilla. Add cocoa powder, flour, and salt, fold in chocolate chips, and spread in the pan, reserving half a cup.
• Make the cheesecake batter: Beat cream cheese and sugar until smooth, add flour, egg yolk, and raspberry preserves, and mix in food coloring if desired.
• Drop spoonfuls of cheesecake batter onto brownie batter, top with remaining brownie batter, swirl with a knife, and add raspberries if desired.
• Bake for 40–42 minutes. Cool completely for at least 3 hours before lifting out and cutting into squares.
• Store cut brownies covered at room temperature for 1 day or in the fridge for up to 1 week.