Preheat your oven to 350°F (175°C). Grease and flour two 9-inch round cake pans.

In a medium bowl, whisk together the flour, baking powder, baking soda, and salt. Set aside.

In a large mixing bowl, cream together the butter and sugar until light and fluffy. Add the eggs one at a time, beating well after each addition. Mix in the lemon juice, zest, and vanilla extract.

Gradually add the dry ingredients to the wet mixture, alternating with the milk. Mix until just combined. Fold in the blueberries gently.

Divide the batter evenly between the prepared cake pans.

Bake in the preheated oven for 25-30 minutes, or until a toothpick inserted into the center of the cake comes out clean.

Allow the cakes to cool in the pans for 10 minutes, then remove from pans and transfer to a wire rack to cool completely.

In a medium bowl, beat the cream cheese and butter until smooth. Gradually add the powdered sugar, lemon juice, and vanilla extract, beating until fluffy.

Once the cakes are cooled, slice each cake layer horizontally to create four layers. Place the first layer on a serving plate and spread a layer of frosting on top. Repeat with remaining layers.

Coat the outside of the cake with a thin layer of frosting to trap any crumbs. Chill for 30 minutes, then apply a final layer of frosting.

Top with fresh blueberries and lemon slices. Use a piping bag to create decorative swirls with remaining frosting.

Serve the cake chilled or at room temperature. Slice with a sharp knife for clean cuts.

Store leftover cake in an airtight container in the refrigerator for up to 3 days. Allow to come to room temperature before serving.