Preheat your oven to 350°F (175°C). Lightly grease a 9x13-inch baking dish.
Spread the lemon pie filling evenly across the bottom of the dish.
In a medium bowl, beat the cream cheese, powdered sugar, and vanilla extract until smooth. Drop dollops of the cream cheese mixture over the pie filling.
Sprinkle the dry cake mix evenly over the top—do not mix it in.
Drizzle the melted butter evenly over the dry cake mix, making sure to cover as much as possible.
Bake for 40-45 minutes, or until the top is golden brown and bubbly.
Let cool slightly before serving. Enjoy warm with ice cream or whipped cream!