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. Add vanilla and sour cream. Pour evenly over the brownie layer.
04 - Bake for 45–50 minutes until center is just set and edges are lightly golden. Cool completely at room temperature, then refrigerate for at least 2 hours.
05 - Melt caramels with heavy cream in a saucepan or microwave, stirring until smooth. Pour over chilled cheesecake and spread gently. Refrigerate 30 minutes until set. Slice into bars and serve.