In a large mixing bowl, cream together the softened unsalted butter and powdered sugar using an electric mixer on medium speed until light and fluffy, about 2-3 minutes.

Mix in the vanilla extract until fully incorporated.

In a separate bowl, whisk together the all-purpose flour, finely ground almonds, and salt. Gradually add this dry mixture to the butter mixture, stirring until just combined.

Wrap the combined dough in plastic wrap and refrigerate for at least 1 hour.

Preheat your oven to 350°F (175°C) and prepare a baking sheet lined with parchment paper.

Roll the chilled dough into 1-tablespoon sized balls, creating an indentation in each ball. Fill with blueberry jam and reshape to seal.

Bake in the preheated oven for 12-15 minutes, or until the edges are lightly golden.

Allow cookies to cool for about 5 minutes before transferring to a wire rack and dusting with additional powdered sugar.