Preheat the oven to 350 degrees F. Grease the two 9-inch round baking pans with butter, line the bottom with parchment paper, then butter the parchment and sprinkle flour on top.

In a large mixing bowl, sift the cake flour, then add the baking powder, baking soda, and salt. Whisk until combined. Toss the blueberries with 1 tablespoon of the flour mixture and set aside.

In a stand mixer, mix the unsalted butter, granulated sugar, and lemon zest on high speed until pale and fluffy (about 3-5 minutes).

Add the eggs one at a time, mixing well after each addition. Then add the vanilla extract.

In a measuring cup, combine the whole milk, sour cream, and fresh lemon juice. Gradually mix the milk and flour mixtures into the butter mixture, alternating in thirds until just combined. Gently fold in the blueberries.

Divide the batter evenly between the prepared pans. Bake in the preheated oven for 30-35 minutes, checking for doneness with a toothpick.

Allow cakes to cool in the pans for 20 minutes before transferring to wire racks to cool completely.

In a mixing bowl, whip the cream cheese and butter until fluffy. Add the vanilla extract and gradually add powdered sugar, mixing until smooth. If runny, refrigerate to thicken.

Once the cakes are completely cool, spread frosting on the top of one cake, place the other cake on top, and frost the entire cake.