Preheat oven to 350°F (180°C). Grease and flour a 9×13-inch baking dish or 3×7-inch pans.
Sift cake flour, baking powder, baking soda, and salt into a medium bowl.
In a separate bowl, whisk buttermilk and lemon juice until slightly curdled.
In a large bowl, beat softened butter until creamy. Gradually add sugar, then lemon zest and vanilla extract.
Add eggs, one by one, beating well after each addition. Gradually mix in the flour mixture.
Fold in the buttermilk-lemon mixture until fully incorporated.
Toss blueberries with 2 teaspoons flour to coat, then gently fold into the batter.
Pour batter into prepared pans and bake for 25–30 minutes, or until a toothpick inserted in the center comes out clean.
Let the cakes cool completely in the pans before frosting.
For the cream cheese frosting: beat cream cheese and softened butter at medium speed until smooth. Gradually add powdered sugar and lemon juice, then add whipping cream as needed for desired consistency.
Spread frosting between cooled cake layers and on the top and sides.
Slice and serve.