Cranberry Jelly

4 cups fresh cranberries
2 cups sugar
2 cups boiling water
salt

Wash and pick over the cranberries. Put the berries in a saucepan and cover with boiling water. As soon as the water begins to boil again, cover with lid and boil 3 – 4 minutes, or until the skins burst. (Instructions are for firm berries; ripe berries require a few minutes longer.) Put through a strainer.
Stir sugar into the puree. Put over the heat and bring to a rolling boil. Boil for 5 minutes, skim, and pour into a wet mold.