Begin preparing the crust first by using a stand mixer or a large bowl with a hand mixer to mix together the 15.25 ounce box of cake mix, ½ cup melted butter, and 1 large egg until it forms a soft dough.
Using the same stand mixer bowl or large mixing bowl, add the 4 cups powdered sugar, 8 ounces softened cream cheese, and 2 remaining large eggs to make the cream cheese mixture. Mix the ingredients until smooth.
Place the baking dish into the preheated oven and bake at 300 degrees F. for about 40 to 50 minutes or until the top is puffy and lightly golden brown. Allow the bars to cool completely before cutting.