1Preheat oven to 350 degrees F (175 degrees C). Grease and flour two 8-inch pans.
2Beat cake mix, water, egg whites, vegetable oil, and lemon extract together in a bowl using an electric mixer on medium speed until batter is well combined, about 2 minutes. Pour batter into prepared pans.
3Bake in the preheated oven until a toothpick inserted in the center of the cake comes out clean, 25 to 30 minutes. Cool in pans for 10 minutes before transferring it to a wire rack to cool completely.
4Beat cream in a chilled bowl using an electric mixer until soft peaks are almost forming into stiff peaks; place bowl in refrigerator.
5Beat cream cheese, sugar, and vanilla extract together in a separate bowl using an electric mixer until smooth and creamy. Fold whipped cream into cream cheese mixture.
6Place 1 cake on a plate; top with blueberry pie filling. Place second cake atop blueberry filling. Generously frost cake with whipped cream cheese frosting.
Footnotes
Tip
Aluminum foil helps keep food moist, ensures it cooks evenly, keeps leftovers fresh, and makes clean-up easy.