Preheat your oven to 350°F (175°C). Line the bottom of a 9-inch (23cm) springform pan with parchment paper. In a medium bowl, whisk together the melted butter and granulated sugar until well combined. Whisk in 2 large eggs and salt until glossy. Fold in the cocoa powder and all-purpose flour until just combined. Spread the batter evenly into the pan and bake for 15 minutes. Lower the oven temperature to 325°F (160°C).

In a large bowl, beat the softened cream cheese on medium speed until perfectly smooth. Add the granulated sugar and beat for another 2 minutes. Add the 3 large eggs one at a time, mixing on low speed just until combined. Gently fold in the sour cream and vanilla extract. Pour gently over the slightly cooled brownie crust.

Bake at 325°F (160°C) for 55-60 minutes until the edges are puffed and set, but the center still has a slight jiggle. Turn the oven off, crack the door slightly, and let the cheesecake cool inside for 1 hour. Chill in the refrigerator for at least 6 hours.

In a small saucepan over medium heat, melt the butter and brown sugar. Pour in the heavy cream and salt. Let simmer for 3-4 minutes until glossy and amber-colored. Remove from heat, let cool slightly, and pour over the chilled cheesecake.

Toast the pecans in a dry skillet over medium heat for 3-5 minutes, then pile them on top of the caramel. In a microwave-safe bowl, heat the remaining heavy cream and pour over the dark chocolate chips. Stir until smooth. Drizzle the ganache in overlapping zigzags across the pecans.