Preheat your oven to 350°F (175°C) and lightly grease a 9-inch square glass baking dish.
In a large mixing bowl, combine the brownie mix with one egg, 1/4 cup of water, and vegetable oil.
Mix until fully incorporated, about 50 strokes.
Pour the batter into the prepared baking dish.
Bake for 25 to 30 minutes, or until a toothpick inserted 1 inch from the edges comes out clean.
Once baked, remove from the oven and allow the brownies to cool completely for about 30 minutes.
In another large bowl, whisk together the condensed milk, the remaining 1/2 cup of water, and the pudding mix until smooth.
Gently fold in 8 ounces of whipped topping until no streaks are visible.
In a trifle bowl or a glass serving dish, create layers by placing half of the brownie squares at the bottom.
Add half of the pudding mixture on top, followed by half of the whipped topping.
Repeat these layers.
For garnish, shave some chocolate over the top.
Cover and refrigerate for 8 hours before serving.
Once chilled, cut the brownies into 1-inch squares and serve.