1. Preheat oven to 350°F (175°C). Grease or line a 9×13-inch baking pan with parchment paper.

2. In a large bowl, mix melted butter and sugar until combined.

3. Add eggs one at a time, mixing well after each, then stir in vanilla.

4. In a separate bowl, whisk flour, cocoa powder, baking powder, and salt.

5. Gradually add dry ingredients to wet ingredients, mixing just until combined.

6. Fold in chocolate chips.

7. Spread about two-thirds of the brownie batter evenly into the prepared pan.

8. In another bowl, beat cream cheese until smooth.

9. Add sugar and mix until combined, then beat in egg and vanilla.

10. Add food coloring if using and mix until evenly colored.

11. Spoon cheesecake mixture evenly over the brownie layer.

12. Drop spoonfuls of remaining brownie batter over the cheesecake layer.

13. Use a knife or skewer to gently swirl the batters together.

14. Bake for 30–35 minutes until edges are set and center has moist crumbs.

15. Cool completely, then refrigerate at least 4 hours before slicing.

16. Cut into squares and serve chilled or slightly room temperature.