1: Preheat oven to 350 degrees.
2: Using an electric hand mixer, mix cake mix, 1 egg, and softened stick of butter together until combined.
3: Pat down into a 9x13 pan (using parchment paper is optional).
4: Mix together remaining ingredients - eggs, cream cheese, powdered sugar, and vanilla and pour over cake crust.
5: Bake at 350 for 10 minutes.
6: Reduce heat to 325 and bake for 45-50 minutes.
7: Let cool completely before cutting. Cut into squares and store any remaining bars in the refrigerator in an airtight container.
