• Preheat oven to 350°F.

Make the Brownie Base

• Spray a 9-inch springform pan with cooking spray, and line the bottom with parchment paper. Set aside.
• Combine the butter and chocolate chips in a large, microwave-safe bowl.
• Heat in the microwave in 30-second increments, stirring between each one until the chocolate is completely melted and smooth.
• Add the sugar, cocoa powder, baking soda, and salt, and beat with a whisk until combined.
• Beat in the eggs and vanilla extract, then fold in the flour until thoroughly mixed.
• Pour the brownie batter into the prepared springform pan and bake for 15 minutes.
• Let the brownie base rest and lower the oven temperature to 325°F.

Prepare the Cheesecake Filling

• In a large bowl, use an electric mixer to mix the cream cheese, sugar, cocoa powder and flour until smooth.
• Add the melted chocolate and vanilla extract.
• Mix in the eggs, one at a time, until just mixed in.

Bake the Cheesecake

• Pour the cheesecake filling over the brownie base and bake for 40 minutes or until the cheesecake is only slightly jiggly in the center.
• Turn off the oven but leave the cheesecake inside for one hour with the door closed.
• After an hour, let the cheesecake cool on a cooling rack until it reaches room temperature.

Make the Chocolate Ganache

• Combine the chocolate chips and heavy whipping cream in a small, microwave-safe bowl.
• Heat in the microwave in 30-second increments, stirring between each time until the ganache is smooth.
• Pour the ganache on top of the cheesecake and spread it out evenly.
• Sprinkle the rainbow chocolate candies on top.

Chill and Serve

• Cover with plastic wrap, and chill for at least 3 hours, ideally overnight, so the brownie base firms up and the cheesecake and ganache set properly.
• Remove the cheesecake from the springform pan and carefully transfer it to a cake stand or platter. Serve chilled.