01 -
Put the blueberries, starch, sugar, vanilla, and lemon juice into a pot. Let it heat up slowly on medium for about half an hour. Cool when thickened.
02 -
Mix salt, baking powder, and flour with a whisk. Keep it aside.
03 -
Beat your butter and sugar together until it feels soft and airy. Mix in the vanilla and egg until the texture is creamy and light.
04 -
Gradually add the dry blend into the butter mix. Stir everything just until the dough takes shape.
05 -
Fold the cooled blueberry jam gently into your cookie dough.
06 -
Scoop 2 tbsp-sized dough balls onto baking sheets with parchment paper, then sprinkle sugar on top if you want.
07 -
Pop into a preheated oven at 350°F (175°C) for 10-13 minutes. Edges should toast slightly golden. Let sit on the tray a few minutes, then move to a rack to finish cooling.