Preheat oven to 350°F. Grease a 9x13 inch baking pan. Prepare brownie mix according to package directions, adding the extra egg for a more cake-like texture.
Bake brownies for 25-30 minutes until a toothpick inserted comes out with moist crumbs. Cool completely in pan on wire rack.
Beat cream cheese with powdered sugar until smooth and creamy. Gently fold in one container of whipped topping.
Spread cream cheese mixture evenly over cooled brownies. Set aside.
In a large bowl, whisk together both pudding mixes with cold milk for 2 minutes until thickened. Let sit 5 minutes.
Pour pudding mixture over cream cheese layer. Top with remaining whipped topping, spreading gently to cover completely.
Sprinkle mini chocolate chips over top and drizzle with chocolate syrup if desired.
Cover tightly with plastic wrap touching the surface. Refrigerate at least 4 hours or overnight before serving.
Cut into squares with a sharp knife dipped in hot water. Serve chilled.