Carefully pick over the berries, removing any leaves, foreign objects, or spoiled berries.
Put the berries in a mixing bowl, and pour the sugar over them.
Use two large forks or a potato masher to mash the sugar into the raspberries until they are liquefied and there is no trace of whole berries left.
(A blender is not good for this, because it will pulverize some of the raspberry seeds, which should remain intact.)
Transfer to jars and refrigerate for two days before using.
Sugared raspberries will keep for one year or longer under refrigeration.