01 - Preheat oven to 350°F. Line a 9x13-inch baking pan with parchment paper or lightly grease with butter.
02 - In a mixing bowl, combine yellow cake mix, melted butter, and 1 egg. Mix until a soft, thick dough forms.
03 - Press the dough evenly into the bottom of the prepared pan using your hands or a spatula to create a uniform layer.
04 - In a separate bowl, beat cream cheese until smooth. Add eggs one at a time, mixing well after each. Blend in powdered sugar, lemon juice, lemon zest, and vanilla extract until fluffy and smooth.
05 - Pour the lemon mixture over the base and spread evenly. Bake for 35-40 minutes until edges are set but center remains slightly jiggly.
06 - Let cake cool completely in the pan before cutting into squares. Dust with additional powdered sugar if desired.