1. Preheat oven to 350°F (175°C). Line an 8×8-inch baking pan with parchment paper, leaving an overhang for easy removal.

2. In a medium bowl, whisk together melted butter, sugar, eggs, and vanilla until smooth.

3. Stir in cocoa powder, flour, salt, and baking powder just until combined. Spread brownie batter evenly into the prepared pan.

4. In a separate bowl, beat cream cheese, sugar, egg yolk, and vanilla until smooth.

5. In a small bowl, mix raspberry jam and lemon juice; fold in raspberries if using.

6. Drop spoonfuls of cheesecake mixture and raspberry mixture alternately over the brownie batter.

7. Use a knife or skewer to gently swirl the layers together to create a marbled effect.

8. Bake for 28–32 minutes, or until the center is just set (do not overbake).

9. Cool completely in the pan, then refrigerate for 1–2 hours to firm.

10. Once chilled, use a heart-shaped cookie cutter to cut out brownie hearts.

11. Dust with powdered sugar or drizzle with melted chocolate before serving.