In a large mixing bowl, cream together the softened unsalted butter and powdered sugar until light and fluffy.

Add the vanilla extract and mix until fully combined, achieving a creamy consistency.

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

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

Preheat your oven to 350°F (175°C), lining baking sheets with parchment paper.

Scoop out about 1 tablespoon of dough, roll it into a ball, and create an indentation in the center. Fill with blueberry jam and reshape the cookie.

Place on the baking sheets and bake for 12-15 minutes until edges are lightly golden.

Allow the cookies to cool for 5 minutes before rolling in powdered sugar. Dust again when completely cool.