Preheat your oven to 325°F (160°C). Grease a springform pan with non-stick spray or line it with parchment paper.

Melt together bittersweet chocolate and unsalted butter until smooth. Stir in granulated sugar, followed by eggs and vanilla extract until well combined. Gently fold in flour, cocoa powder, and salt until just mixed. Finally, add semi-sweet chocolate chips and pour the batter into your prepared pan evenly.

Bake the brownie base for approximately 25 minutes until set around the edges but still slightly soft in the center. Let it cool completely.

Beat softened cream cheese until creamy and smooth. Gradually mix in granulated sugar, followed by vanilla extract, cocoa powder, salt, sour cream, and eggs.

Pour the cheesecake mixture over the cooled brownie base evenly.

Bake for about an hour until set around the edges but still slightly wobbly in the center. Turn off your oven and let it cool inside with the door slightly ajar.

After cooling at room temperature for about an hour, transfer your cheesecake to refrigerate for at least four hours or overnight if possible.

Heat heavy cream until just simmering then pour over semi-sweet chocolate chips in a separate bowl. Let it sit for a few minutes before stirring until smooth and glossy.

Once chilled and set, pour ganache over your cheesecake layer allowing it to drip down gently along edges. Top with colorful candy-coated pieces.