Cream together unsalted butter and granulated sugar in a large mixing bowl until light and fluffy, about 3-5 minutes.

Gradually mix in all-purpose flour, baking powder, and salt until a soft dough forms.

Chill the dough for about 2 hours until firm.

Prepare the cream cheese filling by combining cream cheese, blueberry jam, and a dash of salt until smooth.

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

Scoop about 2 tablespoons of dough, flatten it, and place a teaspoon of cream cheese filling in the center, then fold and roll into a ball.

Arrange cookie balls on the baking sheet and bake for 15-20 minutes until edges are golden brown.

Cool on the baking sheet for 5 minutes, then transfer to a wire rack to cool completely.