Preheat oven to 350°F (175°C) and line a baking tray with parchment paper.
In a bowl whisk together flour, baking powder, salt, and cornstarch.
In another bowl beat butter and sugar until light and fluffy.
Add egg and vanilla extract and mix until combined.
Gradually mix dry ingredients into wet ingredients until a soft dough forms.
In a separate bowl mix cream cheese and powdered sugar until smooth.
Scoop cookie dough, flatten slightly, add a small spoon of cheesecake filling and a few blueberries in the center.
Cover with a little more dough and seal gently.
Place on baking tray and bake for 12–14 minutes until edges are lightly golden.
Cool completely before serving for best texture.
