01 - Preheat oven to 350°F. Grease a 9x13-inch baking dish.
02 - Spread the fresh or frozen blueberries and blueberry pie filling evenly in the bottom of the prepared dish. Sprinkle with lemon zest and drizzle with lemon juice.
03 - In a medium bowl, beat together the cream cheese, sugar, egg, and vanilla until smooth.
04 - Drop spoonfuls of the cream cheese mixture over the blueberry layer and gently spread without fully mixing.
05 - Evenly sprinkle the lemon cake mix over the entire surface.
06 - Drizzle the melted butter evenly on top of the cake mix, ensuring most of the surface is moistened.
07 - Bake for 40–45 minutes, or until the top is lightly golden and the edges are bubbling.
08 - Let cool for 15 minutes before serving. Serve warm or at room temperature, optionally with whipped cream or vanilla ice cream.