01 -
Preheat oven to 175°C. Line a baking sheet with parchment paper.
02 -
In a large mixing bowl, cream together the softened butter and granulated sugar until light and fluffy.
03 -
Add the egg and vanilla extract to the creamed mixture, beating until well combined.
04 -
In a separate bowl, whisk together the flour, baking powder, and salt. Gradually blend the dry mixture into the wet ingredients until just combined.
05 -
Portion small amounts of dough and flatten each into a disc. Place 1 teaspoon of blueberry jam in the center, then fold the dough over and seal the edges.
06 -
Arrange filled cookies on the prepared baking sheet. Bake for 12–15 minutes, or until the edges are lightly golden. Allow to cool completely on a wire rack.
07 -
In a small bowl, whisk together powdered sugar and lemon juice until smooth.
08 -
Drizzle the lemon frosting over cooled cookies and garnish with blue sugar crystals.