Preheat the oven to 350 degrees. Line the bottom of two 9-inch round cake pans with parchment paper and coat with nonstick cooking spray.

In a large bowl with an electric mixer, cream together the butter, sugar and lemon zest until light and fluffy, 3-4 minutes.

Add the eggs and vanilla and mix until well-combined, scraping down the sides of the bowl as needed.

In a separate bowl, whisk together the flour, baking powder, soda and salt. Stir the dry mixture into the wet ingredients until partly combined.

Add the buttermilk and lemon juice to the batter, and stir by hand until just combined.

Toss the blueberries with the 2 tablespoons flour and add them to the batter, folding in by hand until just combined.

Spread the batter evenly in the prepared pans and bake for 25-35 minutes until a toothpick inserted in the center comes out clean.

Let the cakes cool for 5-10 minutes in the pans before turning them out onto a cooling rack to cool completely.

For the frosting, whip the softened cream cheese and butter together until light and fluffy, 2-3 minutes.

Add the powdered sugar, lemon zest and lemon juice and mix on low speed until it starts to come together. Then increase the speed and mix until light and creamy.

When the cake has cooled completely, place one round on a platter and spread the top evenly with frosting.

Place the other cake round upside down on the frosting and press gently. Continue frosting until the top and sides are evenly frosted.

Garnish with blueberries and lemon slices, if desired.