In a large mixing bowl, beat the softened butter until smooth and creamy.
Add the brown sugar and granulated sugar continue mixing until well combined.
In a separate bowl, Add the curd and vanilla extract. Beat until smooth and fully incorporated.
Add the curd mixture to the butter mixture and whisk until smooth and fully incorporated.
Gradually add the all-purpose flour, cornstarch, baking soda, and salt.
Mix gently until a soft cookie dough forms and no dry flour remains.
Add the fresh lemon juice and mix until evenly incorporated.
Add the blueberries and extra lemon zest to the dough.
Gently fold the blueberries into the dough, being careful not to crush them.
In a separate bowl, beat the softened cream cheese and icing sugar until smooth and creamy.
Scoop portions of the cookie dough and flatten each slightly. Place a small spoonful of the cream cheese mixture in the center of each portion.
Gently wrap the dough around the filling, sealing the edges completely, and roll into a smooth ball.
Arrange the filled cookie dough balls on the prepared baking sheet, leaving about 2 inches of space between each cookie.
Bake at 350°F (175°C) for 10 to 12 minutes, or until the edges are lightly golden and the centers are set.
Allow the cookies to cool on the baking sheet for a few minutes before transferring them to a wire rack.
Garnish with extra lemon zest if desired, then serve once completely cooled.
