Preheat the oven to 350°F (180°C). Spray three 8-inch round cake pans with nonstick cooking spray, line the bottom of each pan with a parchment paper circle, and set aside.

Add the blueberries and 1 tablespoon of flour to a mixing bowl and toss until all of the berries are coated. Set aside.

In a large mixing bowl, whisk the flour, baking powder, baking soda, and salt together until well combined. Set aside.

In a separate large mixing bowl or measuring cup, whisk the buttermilk, oil, sour cream, lemon juice, and vanilla extract together until well combined. Set aside.

In the bowl of a stand mixer fitted with the paddle attachment or in a large mixing bowl using a handheld mixer, beat the butter on medium speed until smooth.

Add the sugar and lemon zest and mix until it starts to come together, then increase to medium speed and continue mixing for another 4 to 5 minutes or until the mixture is light in color and fluffy.

Mix in the eggs, one at a time, making sure to stop and scrape around the bottom and sides of the bowl after each egg.

Add the dry ingredients in three additions alternating with the buttermilk mixture (begin and end with the dry ingredients) on low speed. Mix in each addition until just combined.

Use a rubber spatula to scrape around the bottom and sides of the bowl to ensure that everything is well combined.

Spread a thin layer of batter into each of the prepared cake pans (about 150 grams per pan).

Gently fold the blueberries into the remaining cake batter, then divide the batter evenly between all three pans. Smooth each one out into an even layer.

Bake for 28 to 33 minutes or until a toothpick inserted into the center of the cakes comes out clean.

Remove from the oven and allow to cool in the pans for about 20 minutes or until they’re cool enough to handle.

Slide a knife around the outside of the cakes, then carefully remove the cakes from the pans, and transfer them to a wire rack to cool completely.

In the bowl of a stand mixer fitted with the paddle attachment or in a large mixing bowl using a handheld mixer, beat the butter on medium speed until smooth.

Mix in half of the powdered sugar on low speed until well combined, then mix in the remaining half of the powdered sugar.

Add the lemon juice and lemon zest and mix on low-medium speed until fully combined.

Add the cubed cream cheese and continue mixing on low speed until fully combined, scraping the bottom and sides of the bowl as needed.

Level the tops of each cake layer with a knife or cake leveler.

Place one of the cake layers on a cake stand, top with ¾ cup of frosting, and smooth it out into one even layer. Place the second layer on top, and repeat the same process with the frosting. Place the third cake layer upside down on top.

Spread a thin layer of frosting all over the cake. This is known as the crumb coat and will catch any crumbs so that they don’t end up in your final layer of frosting. Place the cake in the freezer for 10 minutes to allow the crumb coat to firm up.

Use the remaining frosting to frost the top and sides of the cake. If you plan to pipe some decorations on top, reserve 1 to 1 ½ cups of frosting for later.