Preheat oven to 335° F. Prepare three 7-inch cake pans using cooking spray and parchment circles.

In the bowl of a stand mixer, add in room temperature unsalted butter and granulated sugar. Cream the butter and sugar together on medium speed for 2 minutes using the paddle attachment until light and fluffy.

On medium-low speed, slowly add in the eggs, sour cream, and vegetable oil. Be sure to scrape the bottom and sides of the bowl after the ingredients are added and continue to mix until the ingredients are fully combined.

In a separate mixing bowl, add the cake flour, baking powder, and salt and whisk to combine.

In a liquid measuring cup, combine buttermilk, lemon juice, and lemon zest.

On the lowest speed, slowly add ⅓ of the flour mixture followed by ½ of the buttermilk mixture.

Add in ⅓ of the flour mixture and the remaining buttermilk mixture. Add in the final ⅓ of the flour mixture.

Scrape the bottom and sides of the bowl. Mix the batter on medium low speed for 30 seconds until the batter is smooth. Do not overmix the batter.

Add in blueberries and fold in with a spatula until they are dispersed throughout the batter.

Divide batter evenly between your cake pans (see equipment for sizes). Use a kitchen scale to ensure that the batter is equally divided.

Bake cakes for approximately 35-40 minutes in the oven until the cakes spring back when gently touched or toothpick comes out clean. *Please note that baking times may be different for different size pans.

Remove cakes from the oven and allow them to cool in the pans on a wire rack for 15 minutes. Run a knife or small offset spatula between the cake and edge of the pan to loosen from the edges. Invert the cakes to remove from the pan and cool completely.

In a mixing bowl or the bowl of a stand mixer fitted with a whisk attachment, add room temperature butter and cream cheese. beat on medium speed for 2 minutes, scraping the sides of the bowl occasionally.

Add in half of the powdered sugar and mix until combined on the lowest speed. Add the remaining half and mix to combine.

Add in salt, lemon juice, and lemon zest. Turn the mixer to medium-high speed and whip for 2-3 minutes, scraping the sides of the bowl occasionally.

Place one cake layer on a circular cake board.

Add desired amount of frosting to the top of the cake layer and spread until even.

Add the second cake layer and repeat adding the frosting and smoothing until even.

Add the final cake layer. Be sure that the layers are even both horizontally and vertically.

Frost the cake with a thin layer of frosting to serve as the crumb coat.

Chill the cake for at least 30 minutes.

Frost the cake using the lemon cream cheese frosting.

Decorate with lemon slices and blueberries if desired.