Working quickly, dip the top of each cookie into the glaze and quickly flip it up so that the glazed side is upright. There are two ways to go about this —you can use the bottom of the cookie, which is smooth and flat. This creates a smoother finish. Or you can do what I did, which is dip the top of each cookie into the glaze. Any crags, cracks, or bumps in the cookie's surface will exaggerate the marble look. And for a streakier glaze, use a swooshing motion to pull the cookie surface along the glaze surface to achieve even more streaks. Let any excess drip off and transfer to a wire rack to dry for 3 to 4 hours. Repeat for remaining cookies and garnish with gold leaf if desired.