• Preheat oven to 325℉. Line an 8x8-inch baking pan with parchment paper and lightly grease.
• In a large bowl, whisk together the melted butter, granulated sugar, and brown sugar until smooth.
• Add eggs, egg yolk, and vanilla extract. Mix until well combined.
• Stir in cocoa powder and salt.
• Gently fold in the cornstarch and flour until just combined. Be careful not the over mix.
• Pour the batter into the prepared pan and spread evenly. Bake 30-40 minutes, or until a toothpick inserted in the center comes out mostly clean with a few moist crumbs. Try to avoid over baking.
• Allow brownies to cool completely before adding the ganache.

Make the Ganache:

• Combine chocolate chips and heavy cream in a microwave-safe bowl.
• Microwave in 15-second intervals, stirring after each interval, until the mixture is smooth and glossy.
• Pour the ganache over the cooled brownies and spread evenly.
• Sprinkle generously with the iconic rainbow candy chips.
• Chill the brownies in the fridge 1-2 hours until ganache is set. Then, slice and enjoy!