In a large pot add the water, butter, sugar, and cocoa powder. Cook on medium heat for 2-3 minutes. Then add the oil and vanilla.
Cook the first few ingredients
Whisk in the egg and egg yolk until fully combined and no trace of egg is left behind
Add Egg and Egg Yolk
Add the baking soda, salt, cornstarch, and mix. Gently fold in the flour and chocolate chips.
Add Dry Ingredients
Gently fold in the chocolate chips and half of the M&Ms.
Pour the brownie batter pan lined with foil for easy removal later. Then add the rest of the M&Ms speeding them out on top of the brownies batter.
Pour Batter Into Pan
Don't overbake the brownies. A toothpick in the center should come out with moist crumbs, not completely dry. Cool completely before cutting.
Bake and Cool