How to Make It
Make Easy Sugar Cookies, cut with heart-shaped cookie cutter. Make flood-consistency Royal Icing.
Divide white Royal Icing equally into 4 bowls. Set 1 bowl aside. In the remaining 3 bowls, mix a pink icing; a red icing; and a purple icing.
Pour all 4 icings into a rectangular dish. Swirl to create desired marbled pattern.
Holding a cookie face-down between your thumb and pointer finger, dip the surface of the cookie into the icing, enough to lightly cover the top of the cookie but not spill over the sides. Pull the cookie back up and move your hand up and down to shake off any excess icing. Repeat with remaining cookies.