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 eggs one at a time, mixing well after each addition.
Stir in the lemon zest and lemon juice.
In another bowl, whisk together the flour, baking powder, and salt.
Gradually add the dry ingredients to the wet mixture, alternating with buttermilk.
Fold in the fresh blueberries gently.
Divide the batter evenly between the prepared pans.
Bake for 30-35 minutes or until a toothpick comes out clean.
Allow the cakes to cool in the pans for 10 minutes, then transfer to wire racks to cool completely.