Preheat your oven to 350°F (175°C).

In a large bowl, cream together the butter and sugar until light and fluffy.

Beat in the eggs one at a time, then stir in the vanilla.

In another bowl, whisk together the flour, salt, and baking powder. Gradually blend this into the creamed mixture.

Roll the dough into small balls, about 1 inch in diameter, and place them on a baking sheet.

Use your thumb or the back of a spoon to make an indentation in the center of each ball.

Fill each indentation with a small amount of jam or preserves.

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

Let cool and dust with powdered sugar before serving.