Yes, this Lemon Icing hardens! In fact, it’s based off my u003ca href=u0022https://www.thespeckledpalate.com/easy-sugar-cookie-icing/u0022u003eEasy Sugar Cookie Icingu003c/au003e recipe that’s wildly popular and that also hardens.u003cbr/u003eu003cbr/u003eHowever, this takes about 4-6 hours total.u003cbr/u003eu003cbr/u003ePersonally, I like for mine to sit overnight to ensure the icing is no longer wet in any places, especially the drips.u003cbr/u003eTo make the hardening process faster, let the cookies dry on a wire cooling rack so that no icing pools around the edges. You can also place them in the refrigerator uncovered for a little while to speed up the process, too.