Preheat the oven to 350°F (175°C).
Prepare the crust by mixing graham cracker crumbs and melted butter.
Press the graham cracker mixture into the bottom of a springform pan.
Bake the crust for 10 minutes or until lightly golden.
Melt the chocolate chips in a microwave or over a double boiler.
In a bowl, combine the melted chocolate with sugar, eggs, and flour.
Pour the brownie batter over the baked crust in the springform pan.
In another bowl, beat together cream cheese, sugar, sour cream, and vanilla until smooth.
Spread the cheesecake mixture gently over the brownie layer.
Bake the cheesecake for 45-50 minutes until set.
Allow the cheesecake to cool at room temperature, then chill in the refrigerator for at least 4 hours before serving.
Drizzle with caramel sauce just before serving.