Begin by preheating your oven to 350°F (175°C). Line a baking sheet with parchment paper or a silicone baking mat to ensure your cookies don’t stick and bake evenly.
In a large mixing bowl, use an electric mixer or a sturdy whisk to cream together the softened unsalted butter and granulated sugar until the mixture is light and fluffy, about 2-3 minutes.
Beat in the large egg, vanilla extract, lemon zest, and lemon juice until everything is well combined.
In a separate bowl, whisk together the cornmeal, all-purpose flour, baking powder, and salt.
Gradually add the dry ingredients to the wet mixture, stirring gently until just combined. Be careful not to overmix.
Gently fold in the fresh blueberries using a spatula to avoid crushing them.
Using a spoon or cookie scoop, drop rounded tablespoons of dough onto the prepared baking sheet, spacing about 2 inches apart. Bake for 12-15 minutes or until edges are golden and centers are set.
Allow the cookies to cool on the baking sheet for 5 minutes before transferring to a cooling rack. Serve once completely cooled and enjoy!