In the bowl of a stand mixer fitted with the paddle attachment, cream together the butter, sugar, and brown sugar until light and fluffy (about 2–3 minutes).

Add the egg, maple syrup, and vanilla extract, and beat until the mixture is smooth.

In a separate bowl, whisk together the flour, baking powder, and salt.

Gradually add the dry mixture to the butter mixture, beating until the dough comes together.

Cover the dough and chill it in the refrigerator for 20 minutes.

Preheat your oven to 350°F (175°C).

On a floured surface, roll out the dough to about 1/8-inch thickness.

Using a leaf-shaped cookie cutter, cut out cookies and place them on a lined baking sheet, spacing them 1 inch apart.

Chill the cut cookies for 10 minutes in the refrigerator.

Bake for 9–11 minutes or until the edges are lightly golden brown.

Allow the cookies to cool completely on a wire rack.

For the filling, beat together the butter, 1 cup of confectioners' sugar, maple syrup, and salt.

Gradually beat in the remaining cup of confectioners' sugar until the filling is smooth.

Flip half of the cookies over, spreading about 2 teaspoons of the filling on each. Place the second cookie on top to create a sandwich.