This is one of our all time favorite cakes! It's boasting of bright fresh lemon flavor and brimming with lots of fresh juicy blueberries. Truly a delectable summertime treat!
Preheat oven to 350 degrees F. Butter 2 (9-inch) round baking pans and line the bottom of each with a round of parchment paper. Butter parchment paper and lightly dust pan with flour, shaking out excess.
Sift cake flour into a mixing bowl. Add baking powder, baking soda and salt and whisk for 20 seconds. Toss blueberries with 1 Tbsp of this flour mixture in a bowl. Set flour mixture and coated blueberries aside.
In the bowl of an electric stand mixer, fitted with the paddle attachment whip together butter, granulated sugar and lemon zest on high speed until mixture is very pale and fluffy, about 3 minutes. Scrape down bowl.
Mix eggs into butter mixture one a time, then stir in vanilla extract. Scrape down bowl.
In a 2-cup liquid measuring cup, measure out milk then stir in sour cream and lemon juice.
Add 1/3 of the flour mixture to the butter/egg mixture then mix just until combined. Add 1/2 of the milk mixture and mix just until combined. Repeat mixing in 1/3 the flour mixture then 1/2 of the milk mixture. Finish with the last 1/3 of the flour mixture.
Gently fold in blueberries.
Divide mixture evenly among prepared baking pans and spread into an even layer. Bake in preheated oven until toothpick inserted into center comes out clean, about 30 to 35 minutes.
Cool in baking pans about 20 minutes. Run a knife around edges to ensure cakes are loosened then invert onto wire racks to cool completely. Once cool, frost with cream cheese frosting.
Store in an airtight container in refrigerator, bring to room temp before serving.
Make Cream Cheese Frosting
In the bowl of an electric stand mixer fitter with the paddle attachment, whip butter and cream cheese until light and fluffy.
Add vanilla and powdered sugar and blend several minutes longer until smooth and fluffy (if frosting seems slightly runny, you can chill it in 5 minute intervals in freezer mixing between each until it's slightly thicker before frosting cake).