01 - Preheat oven to 350°F. Grease and flour two 8-inch round cake pans, lining the bottoms with parchment paper.
02 - Whisk together flour, baking powder, baking soda, and salt in a medium bowl. Set aside.
03 - In a large bowl, beat softened butter with sugar until light and fluffy, about 3 minutes.
04 - Add eggs one at a time, beating well after each addition, then mix in lemon zest, lemon juice, and vanilla extract.
05 - Add the flour mixture in three parts, alternating with milk, starting and ending with flour. Mix until just combined.
06 - Toss blueberries with 1 tablespoon flour, then gently fold them into the batter.
07 - Evenly divide batter between prepared pans and smooth the tops. Bake for 30 to 35 minutes until a toothpick inserted in the center comes out clean.
08 - Let cakes cool in pans for 10 minutes, then transfer onto wire racks to cool completely.
09 - Beat cream cheese and butter until smooth. Gradually add powdered sugar, then mix in lemon juice, vanilla extract, and a pinch of salt until fluffy.
10 - Spread frosting on one cake layer, top with second layer, then frost the top and sides. Garnish with additional blueberries and lemon zest if desired.