Prepare the Pan:

Preheat your oven to 350°F (175°C). Line an 8x8-inch baking pan with parchment paper, leaving an overhang for easy removal.

Make the Brownie Batter:

In a mixing bowl, whisk together melted butter and sugar until smooth. Add eggs and vanilla extract, whisking until fully combined. Stir in cocoa powder, flour, salt, and baking powder until just combined. Set aside.

Prepare the Cream Cheese Mixture:

In another bowl, beat the softened cream cheese and sugar until creamy. Add the egg and vanilla extract, mixing until smooth.

Assemble the Brownies:

Pour 3/4 of the brownie batter into the prepared pan, spreading it evenly. Dollop the cream cheese mixture on top in large spoonfuls. Add the remaining brownie batter in smaller dollops. Use a knife or skewer to gently swirl the brownie and cream cheese layers together, creating a marbled effect.

Bake:

Bake for 30-35 minutes, or until the center is just set and a toothpick inserted into the brownie portion comes out with a few moist crumbs.

Cool:

Allow the brownies to cool completely in the pan before lifting them out using the parchment overhang. Slice into squares and serve.