Preheat the oven to 350°F.
In a pan, melt the butter over low heat.
Turn off the heat and add the cocoa powder. Stir until combined.
Pour butter/cocoa mixture into a bowl with the sugar.
Add eggs and vanilla.
Mix well.
Add baking powder to a bowl with the flour and mix to combine. Slowly add it to the wet mixture. Stir until combined.
Pour the batter into the silicone or non-stick pan.
Bake for 15 minutes or until a toothpick inserted near the center comes out mostly clean.
Immediately stick the brownie M&M’s on top of the brownies. The heat will act as a glue.
Let fully cool before cutting into squares.