Preheat oven to 325°F (163°C). Grease a 9-inch springform pan and line the bottom with parchment paper.
In a mixing bowl, whisk together melted butter and sugar until smooth.
Add eggs and vanilla extract to the mixture and stir until combined.
Add cocoa powder, flour, salt, and baking powder and stir until just incorporated.
Pour brownie batter into the prepared pan and spread evenly.
Bake for 15 minutes and allow to cool slightly while preparing cheesecake layer.
Beat softened cream cheese and sugar together until smooth using a mixer.
Add eggs one at a time, then mix in vanilla extract.
Pour cheesecake batter over the partially baked brownie layer.
Warm caramel sauce slightly and drizzle over cheesecake layer, swirling with a knife.
Wrap the pan in foil and place it in a water bath if desired.
Bake for 50–60 minutes until the center is just slightly jiggly.
Cool for 1 hour at room temperature, then refrigerate for at least 4 hours or overnight.
Slice with a warm knife for clean edges and serve with extra caramel if desired.