Preheat your oven to 350°F (175°C) and grease a baking pan.
In a mixing bowl, combine the yellow cake mix, melted butter, chopped pecans, cream cheese, eggs, vanilla extract, and powdered sugar. Mix until smooth.
Pour the mixture into the prepared baking pan and spread evenly.
Bake for 40 minutes or until the top is golden brown.
For the topping, mix together the melted butter and chopped pecans, then sprinkle over the cake after it has cooled slightly.
Notes
Allow the cake to cool completely before serving for best results.