The burfi mixture is still sticky because it needs to be cooked for a few more minutes. The stickiness comes from the sugar in the 7 cup burfi mixture when it has not formed 1 or 2 string consistencies. When making burfi a 1 or 2 string consistency is required. As we are not making the sugar syrup separately you must make sure that the burfi mixture is cooked well. The ghee should release from the sides and the barfi mixture should look like one molten mass with some bubbles. If the mixture looks dense, hard or dry, then sprinkle some water or milk on top to add moisture while cooking.