Beat 6 oz of cold cream cheese with 3 tbsp of granulated sugar and ½ tsp of vanilla until smooth, about 2-3 minutes. Scoop into 18 portions, flatten, and freeze for at least 1 hour.

Combine 12 oz of fresh blueberries with ¼ cup of granulated sugar in a saucepan and cook over medium heat for about 40 minutes until thickened. Refrigerate until cool.

Whisk together 2¾ cups of flour, ½ tsp of baking powder, ½ tsp of baking soda, and ½ tsp of salt. In another bowl, mix 1 cup of sugar with 2 tbsp lemon zest and 1 cup of butter. Cream until fluffy, then incorporate 1 egg and 2 tsp of vanilla. Gradually add dry ingredients.

Preheat oven to 350°F (175°C). Portion cookie dough, flatten, add blueberry jam in the center, cover with another dough disc, and seal edges. Repeat until all dough is used.

Roll each cookie in ¼ cup sugar and bake for 11-12 minutes until edges are golden and centers are soft. Cool on the baking sheet for 10 minutes before transferring to a wire rack.