Wikipedia Article About Pureed prunes on Wikipedia Lekvar or prune butter is a very thick puree of pure fruit, usually prunes or apricots used in filled Kipfels, pastries, and cookies. It is jam-like so that it will not ooze out of the item it is used in. Lekvar is of East European descent, the first use of the term in literature was from before 1350. The mixture is prepared by cooking the fruit in water until the fruit softens. It is then cooked over the stove with sugar, adding water so that it does not burn. After it is sufficiently soft, the mixture is blended up together.