Line a 8x8" baking pan with parchment paper or tin foil, set aside.
In saucepan melt your butter then stir in your sugar until combined.
Remove from eat and stir in your cocoa powder until completely blended.
Add in your vanilla and stir.
Add in your eggs one at a time making sure to stir very well after each addition.
Slowly mix in your flour until combined then fold in about 1/2 cup of your M&M's.
Pour into prepared baking dish and bake for about 25-30 minutes or until toothpick inserted in center comes out clean, remove from stove and cool completely.
To make your ganache add your chocolate chips to a heat proof bowl.
On stove add your cream to a small sauce pan and heat until just simmering.
Pour your cream over the chocolate chips and cover for about 5-7 minutes then whisk together until creamy.
Pour and spread over your cooled brownies and sprinkle with remaining M&M's.
Chill for about 30 minutes or until ganache is set.