Hanukkah Gelt Cookies

In a small bowl, sift and mix flour, cornstarch, baking powder, baking soda, and salt; set aside.
In the bowl of a stand mixer fitted with the paddle attachment, beat butter and both sugars on medium speed until light and fluffy, about 3 minutes.
Add vanilla and eggs (one at a time); mix to combine.
Reduce speed to low and gradually add flour mixture, mixing until just combined. Be sure to scrape the sides of the bowl during mixing. Next, slowly mix in the chocolate coins.
Cover the bowl and place it in the refrigerator for a minimum of two hours, up to 12 hours.
Preheat oven to 350°F/180°C.
Line two baking trays with parchment paper.
Using a cookie scoop or two tablespoons, drop heaping portions of dough about 1- inch (2 cm) apart.
Bake until cookies are golden around the edges but still soft in the center, 8 to 12 minutes.
Remove from oven, and let cool on the baking sheet 2 to 5 minutes.
Transfer cookies to a wire rack and let cool completely.