Preheat your oven to 350°F (175°C). Grease and flour the 9-inch round cake pan.
In a bowl, whisk together the flour, baking powder, baking soda, and salt. Set aside.
In a separate mixing bowl, beat together the softened butter and granulated sugar with an electric mixer until light and fluffy, about 2-3 minutes.
Add the eggs one at a time, mixing well after each addition. Then, mix in the vanilla extract and lemon zest.
Slowly add the dry ingredients to the butter mixture, alternating with the buttermilk. Begin and end with the flour mixture, mixing until just combined.
Gently fold in the blueberries, being careful not to crush them.
Pour the batter into the prepared cake pan, smoothing the top with a spatula.
Bake for 30-35 minutes, or until a toothpick inserted in the center comes out clean.
Allow the cake to cool in the pan for 10 minutes, then transfer it to a cooling rack to cool completely.
Once the cake is cooled, drizzle lemon juice over the top and dust with powdered sugar if desired before serving.