Slatko refers to different Serbian preserves that are made from seasonal fruit, and slatko od šljiva is a popular variety made with plums, preferably medium-sized local plums such as Prunus domestica. The fruit is typically pitted, peeled, and boiled in syrup before it is chilled and placed in jars.
Occasionally, plums are first placed in a mixture of water and Calcium hydroxide (slaked lime)—which helps to maintain the consistency of the fruit. Lemon rind, scented geranium (rozetla), or vanilla can be added as flavorings.