Preheat your oven to 335°F (170°C) and prepare three 7-inch cake pans with cooking spray and parchment paper.

In a stand mixer, cream together the unsalted butter and granulated sugar until light and fluffy.

Add in the eggs, sour cream, and vegetable oil, mixing until fully combined.

In a separate bowl, whisk together the cake flour, baking powder, and salt.

Whisk together the buttermilk, lemon juice, and lemon zest, then alternate adding this and the dry mixture to the batter until just smooth.

Fold in the fresh blueberries gently with a spatula.

Divide the batter into the prepared pans and bake for 35-40 minutes until a toothpick comes out clean.

Allow the cakes to cool in the pans for 15 minutes before transferring to a wire rack to cool completely.

In a stand mixer, beat the room temperature butter and cream cheese together until creamy, then add powdered sugar and mix until incorporated. Blend in lemon juice and zest.

Once the cake layers are cool, spread frosting between layers and on the exterior of the cake. Decorate as desired.