Prep and Bake Crust: Preheat oven to 325°F. Combine melted butter, sugar, cocoa powder, and salt. Stir in vanilla, then eggs one at a time. Add flour and stir until combined. Spread into a 9-inch springform pan and bake for 15 minutes. Let cool.

Make Cheesecake Filling: In a large bowl, beat the softened cream cheese until completely smooth. Add both sugars and beat until combined. On low speed, mix in heavy cream and vanilla. Add room-temperature eggs one by one, mixing only until just blended.

Assemble and Bake: Pour the cheesecake filling over the cooled brownie crust. Prepare a water bath by wrapping the pan in foil and placing it in a larger roasting pan. Add hot water to the roasting pan. Bake for 65-75 minutes, until the center has a slight jiggle.

Cool Cheesecake: Turn off the oven and crack the door open. Let the cheesecake cool in the oven for 1 hour. Remove from the water bath and cool completely on the counter. Refrigerate for at least 6 hours or overnight.

Add Toppings: Once fully chilled, pour the caramel sauce over the top and spread into an even layer. Melt the dark chocolate and drizzle it in thin lines over the caramel. Garnish the edges with crumbled brownie pieces.

Serve: Run a thin knife around the edge of the cheesecake before releasing the springform ring. Slice with a clean, sharp knife and serve chilled.