Cream together the butter and powdered sugar in a mixing bowl using an electric mixer until light and fluffy.

Whisk together the flour, ground almonds, and salt in a separate bowl. Gradually fold into the wet ingredients until just combined.

Cover the dough and refrigerate for at least 1 hour to solidify the butter.

Preheat the oven to 350°F (175°C) and line a baking sheet with parchment paper.

Remove the dough from the fridge, roll into balls, and make indentations to fill with blueberry jam.

Bake for 12-15 minutes until edges start to turn golden, then cool on the baking sheet.

Roll warm cookies in powdered sugar to coat.