2 cups (12 ounces) fresh or frozen blueberries (do not thaw if frozen)
2 tablespoons all-purpose flour
WHIPPED LEMON CREAM CHEESE FROSTING:
12 ounces cream cheese, softened to room temperature
1/2 cup (1 stick, 4 ounces) butter, softened to room temperature
4 1/2 cups (18 ounces) powdered sugar
1 to 2 teaspoons fresh lemon zest
1 tablespoon fresh lemon juice
2 tablespoons heavy cream
Fresh lemon slices
Preheat the oven to 350 degrees. Line the bottom of two 9-inch round cake pans with at least 2-inch sides with parchment paper and coat with nonstick cooking spray (see note above for pan variations). Set aside.
In a large bowl with an electric mixer (or in the bowl of an electric mixer fitted with the paddle attachment), cream together the butter, sugar and lemon zest until light and fluffy, 4-5 minutes (don't cut down the time on this step).
Add the eggs and vanilla until well-combined, 1-2 minutes, 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 and mix on low speed until just combined and a few dry streaks remain.
Add the buttermilk and lemon juice to the batter, and stir by hand, folding the batter until just combined.
In another bowl, toss the blueberries with the 2 tablespoons flour (see note above). Add the blueberries and remnants of flour to the batter and fold in by hand with a spatula or wooden spoon until just-combined. Overmixing may result in a tough, dry cake.
Spread the batter evenly in the prepared pans and bake for 35-40 minutes until just baked through. The top will spring back lightly to the touch and a toothpick inserted in the center should come out with moist crumbs but not wet batter.
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 cream cheese and butter together with a handheld electric mixer or with an electric stand mixer fitted with the paddle attachment until light and fluffy, 2-3 minutes. Add the powdered sugar, lemon zest and lemon juice and mix on low speed (so the powdered sugar doesn't fly everywhere) until combined. Increase the speed to medium and mix until creamy, 1-2 minutes. Add the heavy cream and whip the frosting until very light and fluffy, 2-3 minutes.
When the cake has cooled completely, place one round on a platter or plate and spread the top evenly with frosting. Place the other cake round upside down on the frosting and press just lightly. Continue frosting with a thin spatula or offset spatula until the top and sides of the cake are evenly frosted. Garnish with blueberries and lemon slices, if desired.
This cake, once frosted, lasts very well in the refrigerator for several days (I've made it up to two days in advance before serving). Take it out an hour or two before serving or serve chilled, your choice!
Zest the lemon(s) before juicing them (it will cut down on the number of lemons you need to use). Speaking of number of lemons, you'll need about 4-5 lemons for this recipe, plus more if you want to garnish the cake with lemon slices.
As stated in the ingredients list, frozen blueberries work well in this cake. The baked cake is slightly wetter around where the blueberries bake into the cake but it's not too noticeable, in my opinion. Remember not to thaw them first. I've actually noticed that the blueberries don't sink to the bottom of the cake as often with frozen blueberries - I think it's because the flour adheres to the blueberries better, helping them cling to the batter. I've never tried it but I suppose you could try just barely misting fresh blueberries with a bit of water (maybe 1/2 teaspoon max!) before tossing with the flour to help prevent sinkage. To be honest, it doesn't really bother me if the blueberries tend to gravitate toward the bottom of the cake but if you are more particular, there's an idea for you.
Also, the frosting makes for thick layers of frosting in between the cake layers and on the top and sides. If you like a little less frosting-to-cake ratio, you could probably cut down the frosting ingredient amounts or just use less and save the rest of the frosting to spread on other goodies.
I've often spread the batter into 3 8-inch pans (with at least 2-inch sides) but find more often, I simplify and bake it in 2 9-inch layers.