Preheat your oven to 350°F (175°C). Grease a 9×13-inch baking dish and line it with parchment paper, leaving an overhang on the long sides for easy removal.

In a medium bowl, whisk together the flour, baking powder, baking soda, and salt. Set aside.

In a large mixing bowl or stand mixer, cream the softened butter and granulated sugar until light and fluffy.

Add the eggs one at a time, mixing well after each addition. Stir in the vanilla extract and buttermilk until fully combined.

Gradually add the dry ingredients to the wet mixture, mixing just until no flour streaks remain.

Stir in the lemon juice and zest. Gently fold in the blueberries using a spatula.

Pour the batter into the prepared pan and spread it evenly. Bake for 40 to 45 minutes, or until a toothpick inserted in the center comes out with just a few moist crumbs.

Allow the cake to cool completely in the pan or lift it out using the parchment overhang.

To make the glaze, whisk together the powdered sugar and lemon juice until smooth. Drizzle evenly over the cooled cake. Let the glaze set before slicing and serving.