Preheat oven to 350°F (175°C). Lightly grease a 9" x 13" x 2" baking pan.
Combine the cake mix, butter, and egg. Stir in the nuts. (The mixture will be thick.)
Press the mixture evenly into the bottom of the pan.
To make the filling:
Using an electric mixer on medium speed, beat the cream cheese and confectioners' sugar until smooth and well-blended. Add the eggs, one at a time, mixing until combined after each addition.
Pour the mixture over the crust in the pan, and spread evenly.
Bake 40-45 minutes or until filling is set.
Notes
*Cake mixes have gotten smaller over the years, and I've tried a few ways to account for that. For simplicity, I prefer using a single box of cake mix. You'll most commonly find 15.25-ounce mixes and I find those work best with 3/4 cup of butter. However, I've left the original quantities (18.25-ounce mix and 1 cup butter) for those who prefer to make the original version. You'll need to use part of another cake mix for those missing ounces.
Store in an airtight container in the refrigerator up to 5 days.