Preheat your oven to 350°F (175°C). Lightly grease a 9-inch springform pan with butter or non-stick spray. Prepare the brownie batter according to the package instructions, usually mixing with eggs, oil, and water until smooth. Pour the batter into the greased pan and spread evenly. Bake for 25-30 minutes, or until a toothpick inserted comes out with moist crumbs. Cool completely on a wire rack.

Lower the oven temperature to 325°F (160°C). In a large bowl, beat softened cream cheese until smooth. Gradually mix in the sugar, then add the vanilla extract. Add eggs one at a time, beating well after each addition. Blend in sour cream and heavy cream until smooth. Pour the mixture over the cooled brownie base, spreading it evenly.

Drizzle caramel sauce over the cheesecake layer. Using a knife or toothpick, gently swirl the caramel into the cheesecake to create a marbled effect. Avoid overmixing to maintain distinct swirls.

Place the springform pan on a baking sheet to catch any drips. Bake at 325°F (160°C) for 45-50 minutes, or until the edges are set and the center jiggles slightly when shaken. Turn off the oven, leave the door slightly open, and let the cheesecake cool in the oven for 1 hour to prevent cracks.

Transfer the cooled cheesecake to the fridge and chill for at least 4 hours, or preferably overnight. Carefully remove the cheesecake from the springform pan using a knife around the edges if needed. Drizzle with extra caramel sauce and garnish with whipped cream and chocolate shavings before serving.

Slice and serve the Caramel Brownie Cheesecake. Store any leftovers in the refrigerator, covered with plastic wrap or in an airtight container. The cheesecake can be kept for several days or frozen for longer storage.