01 - Preheat oven to 350°F. Grease a 9x13-inch baking dish with cooking spray or butter.
02 - Spread fresh or frozen blueberries and blueberry pie filling evenly across the bottom of the prepared dish. Sprinkle lemon zest over the top and drizzle with lemon juice.
03 - In a medium bowl, beat cream cheese, granulated sugar, egg, and vanilla extract until smooth and creamy using an electric mixer or whisk.
04 - Drop spoonfuls of the cream cheese mixture over the blueberry layer. Gently spread to create an even layer without fully mixing into the fruit filling.
05 - Sprinkle the lemon cake mix evenly over the entire surface, covering the cheesecake and blueberry layers completely.
06 - Pour melted butter evenly over the cake mix, ensuring most of the dry mixture is moistened. The butter will create a crisp, golden topping as it bakes.
07 - Bake for 40 to 45 minutes, or until the top is lightly golden brown and the edges are bubbling with fruit filling.
08 - Let the cake cool for 15 minutes before serving. Serve warm or at room temperature, optionally topped with whipped cream, powdered sugar, or vanilla ice cream.