Preheat your oven to 350°F (175°C). In a medium-sized mixing bowl, combine the all-purpose flour with the chilled butter. Use a pastry cutter or your fingers to mix until the mixture resembles coarse crumbs. Stir in 1 cup of toasted walnuts, ensuring they’re evenly distributed. Press this crumbly mixture firmly into the bottom of an ungreased 13x9-inch baking dish. Pop it into the oven and bake for about 12 to 15 minutes, or until you see a light golden brown color. Once baked, transfer it to a wire rack to cool completely.

In a separate small bowl, beat together the softened cream cheese and powdered sugar using an electric mixer until smooth and creamy. Fold in one carton of the thawed whipped topping gently to combine. Spread this delightful mixture evenly over the cooled crust, making sure to reach all corners.

In a large bowl, whisk together the milk and both packages of instant chocolate pudding mix. Continue whisking for about 2 minutes until it thickens up nicely. Pour this luscious pudding layer over the cream cheese layer, smoothing it out gently with a spatula.

Grab your remaining carton of whipped topping and spread it on top of the chocolate pudding layer. Next, sprinkle the chocolate chunks and the additional toasted walnuts evenly over the whipped topping, adding some visual appeal and crunch.

Cover the dish and refrigerate the dessert for at least an hour—or until it’s cold throughout. This step is crucial as it allows the flavors to meld. Before serving, drizzle some chocolate syrup on top for that extra touch of indulgence. Cut into squares and delight in the layers of goodness.