Preheat your oven to 350°F (175°C). In a microwave-safe bowl, melt 1 cup of unsalted butter. Stir in 2 cups of sugar, then add 4 eggs and 1 tablespoon of vanilla. Mix until blended and glossy.

In a separate bowl, sift together 1 cup of flour, 1 cup of cocoa powder, and 1 teaspoon of salt. Gradually fold the dry ingredients into the wet mixture until just combined.

Grease a 9-inch springform pan, pour in the brownie batter, and bake for 25-30 minutes. The edges should be set, with a slight jiggle in the center.

In a mixing bowl, beat 16 ounces of cream cheese until smooth. Add 1 cup of sugar, 2 eggs, 1 tablespoon of vanilla, and ½ cup of sour cream. Mix until fluffy.

After the brownie layer has cooled for 10 minutes, pour the cheesecake mixture over it and bake for 30-35 minutes until slightly wobbly in the center.

For the caramel sauce, heat 1 cup of sugar in a saucepan, stirring continuously until it melts. Whisk in ½ cup of butter and ½ cup of heavy cream, then add a pinch of sea salt.

Let the cheesecake cool completely, then refrigerate for at least 2 hours. Drizzle warm caramel sauce over the cheesecake before serving.