1. Preheat the oven to 350 F. Grease and line two 8 inch round cake pans with parchment paper.

2. In a medium bowl, whisk together the flour, baking powder, and salt.

3. In a large bowl, beat the butter and granulated sugar until pale and fluffy.

4. Add the eggs one at a time, mixing well after each addition.

5. Mix in the lemon zest, lemon juice, and vanilla extract.

6. Add the dry ingredients in three additions, alternating with the buttermilk, and mix just until combined.

7. Toss the blueberries with 1 tablespoon flour, then gently fold them into the batter.

8. Divide the batter evenly between the prepared pans and smooth the tops.

9. Bake for 28 to 32 minutes, or until a toothpick inserted in the center comes out clean.

10. Cool the cakes in the pans for 10 minutes, then transfer to a wire rack to cool completely.

11. To make the frosting, beat the cream cheese and butter until smooth and fluffy.

12. Add the powdered sugar gradually, then mix in the lemon juice, lemon zest, and vanilla extract until creamy.

13. Place one cake layer on a serving plate and spread frosting over the top.

14. Add the second cake layer and frost the top and sides of the cake.

15. Garnish with extra blueberries and lemon zest, then chill briefly before slicing and serving.