Preheat the oven to 350°F (175°C). Grease and flour an 8-inch (20 cm) round cake pan.
In a medium bowl, whisk together 1 1/2 cups flour, baking powder, baking soda, and salt. Set aside.
In a large bowl, using an electric mixer, cream the softened butter and granulated sugar together until light and fluffy, about 3-4 minutes.
Add the eggs one at a time, beating well after each addition.
Mix in the vanilla extract, lemon zest, and fresh lemon juice until combined.
Alternately add the dry flour mixture and buttermilk to the wet ingredients, beginning and ending with the flour mixture. Mix until just combined; do not overmix.
In a small bowl, toss the blueberries with 2 tablespoons of flour to coat them evenly. Gently fold the blueberries into the batter.
Pour the batter into the prepared cake pan and smooth the top with a spatula.
Bake for 38-42 minutes, or until a toothpick inserted into the center comes out clean.
Remove the cake from the oven and allow it to cool in the pan for 10 minutes.
Run a knife around the edges to loosen the cake, then invert it onto a wire rack to cool completely before serving.