Preheat your oven to 350°F (175°C) and prepare a 9×13 baking dish by spraying it with cooking spray.

In a mixing bowl, combine the brownie mix, egg, melted butter, and milk. Mix until well combined.

Pour the batter into the prepared baking dish and bake for 25-28 minutes, or until a toothpick inserted in the center comes out clean.

Remove from the oven and place on a cooling rack to cool completely.

In a large mixing bowl, combine the cream cheese and vanilla extract. Using a hand mixer, whip until light and creamy.

Gradually add in the powdered sugar, mixing well and scraping down the sides to ensure everything is fully combined.

In a microwave-safe bowl, melt the semi-sweet chocolate and cubed butter in 30-second intervals, stirring until smooth.

Slowly incorporate the melted chocolate mixture into the cream cheese mixture, stirring constantly until combined.

Gently fold in the whipped topping until everything is mixed.

Pour the creamy layer over the cooled brownie base, spreading it evenly with a spatula.

Top with a layer of whipped topping and sprinkle with chocolate shavings or mini chocolate chips.

Refrigerate the brownies until ready to serve.