Preheat oven to 350.
Spray a 9"x13" bar pan or cake pan with non-stick cooking spray.
In bowl of stand mixer beat together your butter, sugars and vanilla until light and fluffy.
Add in your eggs one at a time until incorporated.
In medium sized bowl whisk together flour, cocoa powder, baking powder, cornstarch, and salt until combined.
Alternate adding dry ingredients and milk into mixer until just combined.
Spread your brownie batter into prepared pan and bake in oven for about 20 minutes.
Remove from oven to cool completely.
Once cooled to make your ganache add your chocolate chips to a medium sized bowl.
Heat your heavy cream in microwave for about 1 minute until just bubbling then pour over chocolate chips and let sit for about 5-7 minutes.
Whisk chocolate and cream mixture until smooth and then pour over cooled brownies then sprinkle with candy coated chips.
Let sit for about 30 minutes for the ganache to set up.