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 with lemon zest and drizzle with lemon juice.
03 - Beat softened cream cheese, granulated sugar, egg, and vanilla extract in a medium bowl until smooth and creamy.
04 - Drop spoonfuls of the cream cheese mixture over the blueberry layer. Gently spread to distribute evenly without fully mixing into the fruit.
05 - Sprinkle the lemon cake mix evenly over the entire surface, covering all areas.
06 - Pour melted butter evenly over the cake mix, ensuring most of the dry mix is moistened.
07 - Bake for 40 to 45 minutes until the top is lightly golden brown and edges are bubbling.
08 - Let cool for 15 minutes before serving. Serve warm or at room temperature, optionally topped with whipped cream or vanilla ice cream.