In a large mixing bowl, cream the softened unsalted butter and powdered sugar together for 2-3 minutes until light and fluffy.

Add in the vanilla extract and mix until fully combined.

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

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

Preheat your oven to 350°F (175°C).

Roll the chilled dough into 1-tablespoon balls, create an indentation in each ball, fill it with 1 teaspoon of blueberry jam, and reshape them into balls.

Place the shaped cookies on a parchment-lined baking sheet and bake for 12-15 minutes.

Allow the cookies to cool for about 5 minutes and then roll them in additional powdered sugar.