Preheat your oven to 350°F (175°C). Line a 9x13-inch baking pan with parchment paper or lightly grease it.

In a mixing bowl, combine the yellow cake mix, melted unsalted butter, and one egg. Mix until a soft dough forms, then press into the bottom of the prepared pan.

In another bowl, beat the softened cream cheese until smooth. Add the remaining two eggs and the vanilla extract, then gradually incorporate the sifted powdered sugar until thick and creamy.

Pour the cream cheese filling over the crust in the pan and smooth the top.

Bake in the preheated oven for 35-40 minutes, until edges are golden brown and center is soft and slightly jiggly.

Let the bars cool completely on a wire rack, then refrigerate for at least 2 hours before slicing.