Preheat the oven to 350°F, and spray a 9x13-inch baking dish with non-stick cooking spray. 

In a large mixing bowl, use a hand mixer to combine the flour, softened butter, walnuts, and powdered sugar until a soft dough forms. 

Press the dough into the prepared baking dish, and bake for 10-12 minutes or until the crust is lightly browned. Remove it from the oven, and allow it cool for at least 20 minutes. ½

In a separate large mixing bowl, combine the softened cream cheese, whipped topping, and powdered sugar. Mix the ingredients until they are smooth and creamy.

Scoop the cream cheese mixture onto the cooled crust. Use a spatula to smooth out the mixture and cover the entire crust. Return the dessert to your refrigerator while you prepare the next layer.

In a third large bowl, use a hand mixer to blend the instant pudding mix and milk according to package instructions. Make sure the pudding is completely mixed, then pour it over the cream cheese layer.

Use a spatula to smooth the pudding into an even layer. Place the dish back in the refrigerator for 20 to 30 minutes to set slightly before adding the whipped topping.

After the chocolate pudding has set, carefully add the whipped topping. Spread in an even layer. Top with chopped walnuts if desired.

Transfer the chocolate lasagna back to the refrigerator for 2 hours to allow all the layers to set.

Enjoy chilled. See post for storage options.