01 - Preheat oven to 350°F. Line a 9-inch square baking pan with parchment paper, leaving an overhang for easy removal.
02 - Melt butter in a microwave-safe bowl. Whisk in sugar, eggs, and vanilla until glossy. Sift in flour, cocoa, and salt. Mix just until combined. Spread evenly in the pan.
03 - Beat cream cheese and sugar with an electric mixer until smooth. Add eggs one at a time, beating well after each addition. Mix in vanilla and sour cream until incorporated.
04 - Pour cheesecake mixture evenly over the brownie layer. Bake for 45-50 minutes until the center is just set and edges are lightly golden.
05 - Cool completely at room temperature, then refrigerate for at least 2 hours until firm.
06 - Melt caramels with heavy cream in a saucepan or microwave, stirring until smooth and glossy.
07 - Pour caramel over chilled cheesecake and spread gently. Refrigerate an additional 30 minutes until set. Slice into bars and serve.