
Line two baking sheets with parchment paper. Place 1/2 cup granulated sugar in a small bowl (for rolling). Set aside.
In a medium bowl, whisk together the flour, cornstarch, and salt. Set aside.
In a separate bowl, combine the butter, granulated sugar, and light brown sugar. Beat until light and fluffy, about 2 minutes.
Add the egg yolk and vanilla paste and beat until fully incorporated.
Gradually add in the flour mixture and beat until combined.
Use a 2 tablespoon cookie scoop to portion out the dough. Roll the dough into balls and roll the dough balls in the granulated sugar.
Place the dough balls 2 inches apart on the prepared baking sheets. Use the bottom of your balm to gently flatten the dough balls.
Use the back of a 1/4 teaspoon to gently press an indentation into the center of each cookie (this will be the medal). If edges crack, lightly smooth them with your fingers. Use a chopstick to create the 2 indentations above the teaspoon indentation (this will be the lanyard).
Place the cookies in the refrigerator to chill for 1 hour.
Preheat oven to 375°F.
Bake the cookies for 10-15 minutes, or until edges are lightly golden.
Remove the cookies from the oven and, if needed, gently re-press the indentations. Allow cookies to cool completely on the baking sheets.
Place the white chocolate melting wafers, blue candy melts, and dark chocolate melting wafers in separate piping bags. Heat them in the microwave, checking every 30 seconds, until melted.
Pipe a small amount of white chocolate into the bottom of the lanyard imprints (closest to the circle). Fill the remaining part of the lanyard imprint with the blue candy melt.
For silver medals, pipe white chocolate into the center imprint. For gold medals, pipe dark chocolate in the center imprint.
Let the cookies rest at room temperature until the chocolate has set. Use a clean (never been used with paint) paint brush or q-tip to cover the white chocolate medals with silver luster dust and the dark chocolate medals with gold luster dust.
adapted from Sugar Spun Run.