Preheat your oven to 350°F (180°C) and grease a 9x13 inch cake pan.

In a medium bowl, sift together the cake flour, baking powder, baking soda, and salt; set this mixture aside.

In another bowl, combine the buttermilk and lemon juice; allow it to sit until slightly thickened.

In a large mixing bowl, cream together the unsalted butter, granulated sugar, and lemon zest until the mixture is light and fluffy.

Add the vanilla extract and eggs one at a time, making sure to scrape down the bowl after each addition.

With the mixer on low, alternate adding the dry flour mixture and the buttermilk until fully combined.

Gently fold in the blueberries that have been coated with the two teaspoons of flour.

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

Let the cake cool in the pan before removing it.

For the creamy frosting, beat together the butter, cream cheese, and lemon juice. Gradually add the powdered sugar and whipping cream, mixing to your preferred consistency.

Frost the cooled cake generously and serve it to your delighted guests!