Preheat oven to 350°F (175°C) and line two baking sheets with parchment paper.
In a large bowl, combine melted butter, granulated sugar, and brown sugar.
Whisk in eggs and vanilla extract until smooth.
Add cocoa powder, flour, baking powder, and salt. Mix until a thick dough forms.
Fold in chocolate chips and refrigerate dough for 10 minutes.
In another bowl, beat cream cheese with sugar, egg yolk, and vanilla extract until smooth.
Scoop tablespoons of brownie dough onto prepared baking sheets, spacing 2 inches apart.
Flatten each dough scoop slightly and add a teaspoon of cheesecake filling on top.
Use a toothpick or knife to gently swirl the cheesecake into the cookie.
Bake for 10–12 minutes or until edges are set and centers look slightly soft.
Cool on baking sheet for 5 minutes, then transfer to a wire rack.