Preheat your oven to 350°F (175°C) and prepare a 9x13-inch baking dish by greasing it generously with butter or non-stick spray. Line the bottom with parchment paper for easy removal.

In a medium mixing bowl, whisk together the all-purpose flour, baking powder, baking soda, and salt.

In a stand mixer, add the softened butter and granulated sugar. Mix on medium speed for about 3-5 minutes until light and fluffy.

Gradually add the large eggs, one at a time, mixing well after each addition. Follow with vanilla extract.

Pour in the buttermilk while mixing on low speed until fully incorporated.

Slowly add the dry flour mixture to the wet ingredients, mixing on low speed until just combined. Gently fold in lemon juice, lemon zest, and blueberries.

Pour the batter into the prepared baking dish and bake for 40-45 minutes or until a toothpick comes out with moist crumbs.

Let it cool in the pan for about 10 minutes, then transfer to a wire rack to cool completely.

In a medium bowl, whisk together powdered sugar and lemon juice until smooth and pourable.

Once the cake is completely cool, drizzle the lemon glaze over the top and allow it to set before slicing.