Preheat the oven to 350°F (175°C). Grease the baking pan.

In a mixing bowl, combine melted butter and sugar. Mix well.

Add eggs and vanilla extract, and mix until smooth.

In another bowl, whisk together cocoa powder, flour, salt, and baking powder.

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

Pour the brownie batter into the prepared baking pan and spread evenly.

In a separate bowl, beat the softened cream cheese until smooth.

Add sugar, egg, and vanilla extract. Mix until well combined and creamy.

Spread the cheesecake mixture over the brownie layer in the baking pan.

Bake in the preheated oven for 30-35 minutes, or until the cheesecake is set and the edges are slightly firm.

Allow to cool in the pan before cutting into squares.