With a mixer with the whisk attachment, beat butter and sugar until smooth.

Add eggs and vanilla extract and beat again until smooth.

In a medium bowl, combine flour and baking powder. Switch to a paddle attachment and gradually add the flour mixture to the wet ingredients and blend until combined and a soft dough forms.

Divide dough into two equal portions, form each into a disk and tightly wrap in plastic wrap. Refrigerate for at least 1 - 2 hours or overnight.

Preheat oven to 350 degrees F. Prepare large cookie sheets by lining with parchment paper.

Remove dough from refrigerator and let sit at room temperature for 10 - 15 minutes (or 30 minutes if chilled overnight). Lightly flour a work surface and a rolling pin. Roll out one disk at a time to a 10” circle while lightly sprinkling with more flour as needed, which should give you between ⅛” – ¼“ thickness. Not recommended to roll any thinner.

Cut circles with a 2” or 2 ½” round biscuit cutter and transfer cookies to the prepared baking sheets placing them at least 1” apart. Re-roll scraps and cut out more cookies. Keep the cut cookies chilled until ready to bake.

Bake cookies for 8 - 9 minutes, or until a pale, light-golden colour. Remove from oven and let cookies set on the baking sheet for 1 minute before removing to a rack to cool completely.

Have the pistachios chopped and ready, set aside. Chop white chocolate molding wafers and place in a small heat proof bowl which is placed over a small saucepan of simmering water to create a double boiler. Keep the water simmering and stir until the white chocolate is completely melted and smooth. Remove from heat.

Prepare two large baking sheets by lining them with waxed or parchment paper. Working quickly, dip about one-third to one-half of each cookie into the melted white chocolate coating both sides, let some drip off, and place on prepared baking sheets, spreading them apart. Immediately sprinkle tops with chopped pistachios. Let cookies sit at room temperature to set for 20 – 30 minutes before transferring to a platter.