In a large pot add the water, butter, sugar, and cocoa powder. Cook on medium heat for 2-3 minutes.
Cook the first few ingredients
Let mixture cool for a few minutes then whisk in the oil and vanilla.
Add the Oil & Vanilla
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
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