Prepare the Brownie Layer:

Preheat your oven to 350°F (175°C) and grease a 9-inch square baking pan.

Melt the butter in a medium saucepan over medium heat. Remove from heat and stir in the sugar, eggs, and vanilla extract.

Sift in the cocoa powder, all-purpose flour, salt, and baking powder. Mix until combined.

Pour the brownie batter into the prepared baking pan, spreading it evenly.

Prepare the Cheesecake Layer:

In a medium bowl, beat the cream cheese until smooth.

Add the sugar, egg, and vanilla extract, beating until well combined.

Combine Layers and Add Raspberry Swirl:

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

Spoon the raspberry jam in small dollops over the cheesecake layer.

Use a knife or skewer to swirl the raspberry jam into the cheesecake layer, creating a marbled effect.

Bake:

Bake in the preheated oven for 35-40 minutes, or until the cheesecake layer is set and the edges are lightly golden.

Allow to cool completely in the pan on a wire rack before slicing.