Preheat the oven to 350° F and line 24 muffin cups with paper liners.
Zest the lemons until you have 2 tablespoons. Juice the lemons until you have 1/4 cup and set aside.
In a large bowl, sift together the cake flour, all-purpose flour, baking powder, salt and baking soda. Set aside.
Combine the buttermilk and lemon juice in a large measuring cup with spout. Set aside.
Combine lemon zest, butter, and sugar in the bowl of a stand mixer fitted with the paddle attachment. Beat on low speed until the mixture in smooth and creamy.
Add the eggs one at a time, mixing well and scraping the bowl after each addition, and waiting until all traces of each egg have disappeared before adding the next one.
Add the sour cream and mix until smooth.
Add the dry ingredients in three parts, alternating with adding the wet ingredients in two parts. Keep the mixture at the lowest speed, and mix each time just until the ingredients are combined. Once everything has been added, scrape the side of the bowl and paddle one more time, and stir just until batter is smooth. Fold the blueberries into the batter. Let the batter rest for 15 min. Stir gently before use.
Fill the cupcake liners three-quarters full. Bake until the tops of cupcakes are firm and edges of the cupcake are slightly brown, for about 20 minutes. Let cupcakes cool for 5 minutes in the pan, and move to a cooling rack.
Lemon Cream Cheese Frosting
Put softened cream cheese and butter into a mixing bowl and blend together.
Sift in confectioner's sugar a little at a time and blend until all of it is incorporated.
Mix in the lemon juice and lemon zest.
Spread or pipe your cream cheese frosting onto your cooled cupcakes and enjoy!