Get about 2 quarts of fresh berries (raspberries or loganberries or marion berries or blackberries). Sprinkle about 1/4 cup sugar over them and let them sit for a couple hours. This will leech much of the juice out of them. Pour off the juice and press the berries through cheesecloth. Bring the liquid to a boil and reduce (stirring all the while) by about half. Freeze. This makes under a quart of slush. Since it hasn't been emulsified, it isn't as smooth as the first recipe, but the berry taste is very very intense. (You can emulsify it by cooling the liquid and adding an egg white, but this seems to cut into the taste more then you might expect.)