In a medium bowl, whisk together the flour, baking powder, and salt. Set aside.

In a stand mixer, beat together the butter, granulated sugar, and brown sugar until light and fluffy. Add in the egg and maple extract; continue beating until fully combined.

Gradually add the dry mixture into the wet ingredients using low speed. Mix just until everything comes together.

Divide the dough into two balls and flatten into disks. Wrap in plastic wrap and refrigerate for at least one hour.

Preheat your oven to 375°F (190°C) and prepare baking sheets lined with parchment paper.

Roll out the chilled dough to about 1/4-inch thick and cut out cookie shapes. Place them on prepared baking sheets.

Bake for about 8–10 minutes or until just golden around the edges.

Let them cool on the baking sheet for about three minutes before transferring to wire racks.

Prepare the filling by creaming together soft butter until smooth. Gradually add confectioners' sugar and maple syrup; beat until well combined.

Spread filling onto one side of each cookie and top with another cookie.