Preheat the oven to 350°F (175°C) and prepare a loaf pan by greasing it.

In a bowl, mix the flour, sugar, baking powder, and salt.

In another bowl, cream the butter, then add lemon zest, lemon juice, and eggs, mixing well.

Combine the wet ingredients with the dry ingredients until just mixed.

Fold in the blueberries carefully.

Pour the batter into the prepared loaf pan.

Bake for about 60 minutes, or until golden and a toothpick inserted in the center comes out clean.

Allow to cool before preparing the glaze by whisking powdered sugar with lemon juice and drizzling it over the loaf.