In a separate bowl whisk the flour with the baking powder & salt. Set aside.

In the bowl of your electric mixer (or with a hand mixer), beat the butter until smooth and creamy (about 1 minute). Add the sugar and beat until smooth (about 2 minutes). Beat in the egg & vanilla extract. Gently stir in the flour mixture just until incorporated aftr the mixing.

Wrap the dough in a plastic wrap, and chill the dough for at least 3 hour or until firm.

Preheat oven to 350 degrees F (177 degrees C) with the rack in the middle of the oven. Line two baking sheets with parchment paper.

On a lightly floured surface roll out the dough into a 1/4 inch (.6 cm) thick circle. Cut into rounds, square heart-shaped or any other shapes using a lightly floured cookie cutter. Place on the prepared baking sheets and place in the refrigerator for about 15 minutes. (This will firm up the dough so the cookies will maintain their shape when baked.) Bake for 8 - 10 minutes, or until cookies are very lightly browned. Cool on a wire rack.

#Assemble_Cookies:

Place the cut out cookies on a baking sheet and lightly dust the tops with powdered sugar. Spread a thin layer of jam on the bottom surface of the full cookie (top of cookie will face out). Place the cut-out cookie on top and gently sandwich them together. Using a small spoon or a piping bag, fill the cut-out with a little more jam.

The filled cookies will soften when stored. If you want the cookies to stay crisp, assemble the day of serving. The assembled cookies can be stored in the refrigerator, in an airtight container, for several days.