Preheat your oven to 350°F (175°C) and grease two 9-inch round cake pans.
In a large bowl, cream together the softened butter and sugar until light and fluffy.
Add the eggs one at a time, mixing well after each addition.
Stir in the lemon zest and lemon juice.
In a separate bowl, whisk together the flour, baking powder, baking soda, and salt.
Gradually add the dry ingredients to the butter mixture, alternating with the buttermilk.
Fold in the fresh blueberries gently to avoid crushing them.
Divide the batter evenly between the prepared pans and smooth the tops.
Bake for 30-35 minutes, or until a toothpick inserted in the center comes out clean.
Let the cakes cool in the pans for 10 minutes before transferring to wire racks to cool completely.