Preheat your oven to 350°F (175°C). Grease a 9x13-inch baking dish with butter or cooking spray.

In a large mixing bowl, combine the yellow cake mix, softened butter, and egg. Mix with an electric mixer or whisk until fully combined and smooth.

Pour the cake batter into the prepared baking dish. Use a spatula to spread the batter evenly. Bake in the preheated oven for 20–25 minutes, or until a toothpick inserted into the center comes out clean. Remove from the oven and let it cool slightly.

While the cake base is cooling, prepare the cream cheese topping. In a separate bowl, beat together the softened cream cheese, softened butter, eggs, vanilla extract, and powdered sugar using an electric mixer until smooth and well combined.

Once the cake base has cooled for about 10 minutes, spread the cream cheese mixture evenly over the cake layer.

Return the cake to the oven and bake for an additional 30–35 minutes, or until the cream cheese topping has set and turned golden brown on top. A toothpick should come out clean when inserted into the center of the cream cheese layer.

Allow the cake to cool completely in the baking dish. If you like, sprinkle chopped pecans on top of the cream cheese layer for extra flavor and texture. Slice and serve.