Preheat your oven to 350°F (175°C).
In a large bowl, cream together the softened butter and sugar until light and fluffy.
Add the egg, lemon juice, and lemon zest to the mixture, and beat until combined.
In a separate bowl, whisk together the flour, baking powder, baking soda, and salt.
Gradually add the dry ingredients to the wet mixture, stirring until just combined.
Gently fold in the fresh blueberries.
Drop tablespoonfuls of dough onto a baking sheet lined with parchment paper, spacing them about 2 inches apart.
Bake in the preheated oven for 10-12 minutes or until the edges are lightly golden.
Remove from the oven and allow the cookies to cool on the baking sheet for 5 minutes.
Transfer cookies to a wire rack to cool completely.