Preheat oven to 350°F (175°C). Grease your baking pan and line with parchment paper for easy removal.

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

In a large bowl, beat butter and sugar together for 3–4 minutes until light and fluffy. This step helps create a soft texture.

Add eggs one at a time, mixing well after each addition.

Stir in vanilla extract, lemon juice, and lemon zest for fresh citrus flavor.

Add half of the dry ingredients into the wet mixture and mix gently.

Pour in buttermilk and mix until combined.

Add remaining dry ingredients and fold gently to avoid overmixing.

Toss blueberries with 2 tablespoons flour to prevent them from sinking during baking.

Gently fold blueberries into the batter using a spatula.

Pour batter into prepared pan and spread evenly.

Tap the pan lightly to remove air bubbles.

Bake for 40–45 minutes or until a toothpick inserted comes out with moist crumbs.

Remove from oven and let cool completely in the pan.

Prepare glaze by mixing powdered sugar, lemon juice, and zest until smooth.

Pour glaze evenly over the cooled cake.

Allow glaze to set for 10–15 minutes.

Slice into squares and serve.