Preheat your oven to 350°F (180°C). Grease and flour a 9x13 inch cake pan. If you prefer a layered cake, line the bottom with parchment paper and grease the sides.

Sift together the cake flour, baking powder, baking soda, and salt in a medium bowl. Set aside.

In another bowl, whisk together the buttermilk and lemon juice until well combined.

In a large mixing bowl, cream the softened butter, granulated sugar, and lemon zest until light and fluffy, about 2-3 minutes. Beat in the vanilla extract and add eggs, one at a time, scraping the bowl sides as you go.

With the mixer set to low, alternate adding the dry flour mixture and the wet buttermilk mixture until just combined. Be careful not to overmix!

Toss the blueberries with 2 teaspoons of flour to prevent them from sinking, then gently fold them into the batter.

Pour the batter into the prepared pan and bake for 30-35 minutes, or until a toothpick inserted in the center comes out clean.

Let the cake cool in the pan for about 10 minutes before transferring it to a wire rack to cool completely.

For the frosting, beat the softened butter with cream cheese until smooth. Gradually incorporate lemon juice and powdered sugar until you reach the desired consistency, adding whipping cream if needed.

Serve the cake plain or decorate it with a dusting of powdered sugar, lemon slices, or whipped cream for that extra special touch.