Preheat the oven to 350°F (175°C) and grease the springform pan with unsalted butter.

Melt the unsalted butter in a medium saucepan over low heat. Stir in granulated sugar until well combined. Cool slightly, then whisk in eggs and vanilla until smooth.

Sift together flour, cocoa powder, and sea salt in a separate bowl. Gradually add to wet ingredients, stirring until just combined.

Pour brownie batter into the prepared pan and bake for 25-30 minutes until set around the edges.

Beat cream cheese in a large bowl until creamy. Gradually add sugar, mixing until fully incorporated. Add eggs, vanilla, and sour cream, mixing until smooth.

Pour cheesecake filling over cooled brownie layer and bake for 30-35 minutes until set with a slight jiggle in the center.

In a saucepan, heat granulated sugar over medium heat, stirring until it melts into an amber color. Add butter and cream, stirring until smooth. Mix in sea salt.

Let the cheesecake cool for 1 hour, then drizzle with warm caramel sauce and refrigerate for at least 2 hours.