Preheat oven to 350°F (175°C). Grease and flour two 9-inch round cake pans.
In a large bowl, sift the flour, baking powder, and salt together.
In another bowl, whisk together the sugar and eggs until light and fluffy.
Gradually add the buttermilk to the egg mixture, then stir in the melted butter, lemon zest, and lemon juice.
Add the dry ingredients to the wet ingredients in three parts, alternating with the buttermilk, and mix until just combined.
Gently fold in the fresh blueberries until evenly distributed.
Divide the batter between the prepared cake pans and smooth the tops.
Bake for 25-30 minutes, or until a toothpick inserted in the center comes out clean.
Remove from the oven and let cool in the pans for 10 minutes. Then carefully run a knife around the edges and invert onto a wire rack to cool completely.
While the cakes are cooling, prepare the lemon glaze by whisking the powdered sugar, fresh lemon juice, and lemon zest until smooth.
Once the cakes are fully cooled, slice a thin layer off the tops to create a flat surface if needed.
Place one cake layer on a serving plate, spread a generous layer of lemon glaze, and top with the second cake layer. Gently spread the remaining glaze over the top, allowing some to drip slightly.
Garnish with additional fresh blueberries and lemon zest for a decorative touch.