Step 1

Preheat the oven to 350 degrees. Line a 9x13 inch baking dish with parchment paper and spray with cooking spray. Set aside.

Step 2

To a large bowl, add the granulated sugar, brown sugar, vanilla, salt, whole eggs and yolks and whisk until combined.

Step 3

To a microwave safe bowl, add the butter and chocolate chips. Microwave for 30 seconds, stir, then microwave another 30 seconds and stir. Repeat until melted and smooth.

Step 4

Whisk in the vegetable oil to the melted chocolate.

Step 5

Pour the chocolate mixture into the sugar mixture and mix until fully combined. Gently fold in the flour and cocoa.

Step 6

Pour the brownie batter into the prepared pan and bake until a toothpick inserted in the center comes out clean, 30 to 35 minutes.

Step 7

Place chopped or grated chocolate into a medium microwave safe bowl and set aside.

Step 8

In a large microwave safe bowl combine your sweetened condensed milk and butter.

Step 9

Microwave for 30 seconds and stir. Microwave another 30 seconds.

Step 10

When the butter is melted, carefully add your chocolate chips and stir in until melted. You can also microwave for 15 seconds more until chips are all melted and ganache is smooth.

Step 11

Pour the ganache over the brownies and immediately sprinkle with the rainbow chips.

Step 12

Let cool completely before slicing.