Pro-Tip - If you live in a humid climate such as Florida, it might take longer for your cookies to dry (up to 24 hours). To speed up the process, here's a trick. Turn your oven light on (not the actual oven) and place trays of wet royal icing cookies in the lighted oven for about 30 minutes to help them dry quicker. You could also try a hair dryer on the cool air setting.