Make the Cookie Dough:

1. Cream the Butter and Sugar: In a large mixing bowl, cream the softened butter and sugar together until light and fluffy. This will take about 2-3 minutes.
2. Add the Egg and Lemon: Add the egg, lemon zest, and lemon juice to the butter mixture. Mix until fully combined.
3. Combine Dry Ingredients: In a separate bowl, whisk together the flour, baking soda, baking powder, and salt. Gradually add the dry ingredients to the wet mixture, mixing until just combined.
4. Add the Blueberries: Gently fold in the fresh blueberries, being careful not to crush them. If using frozen blueberries, make sure they are drained and as dry as possible before adding.

Bake the Cookies:

5. Preheat the Oven: Preheat your oven to 350°F (175°C) and line a baking sheet with parchment paper.
6. Scoop the Dough: Using a cookie scoop or spoon, scoop tablespoon-sized portions of dough and place them onto the prepared baking sheet, spacing them about 2 inches apart.
7. Bake the Cookies: Bake the cookies for 12-15 minutes, or until the edges are lightly golden, and the centers are set.
8. Cool the Cookies: Let the cookies cool on the baking sheet for 5 minutes before transferring them to a wire rack to cool completely.