Put berries in pan over slow heat, let them come to boil slowly and boil about 6 minutes. Add sugar and boil 6 more minutes.
Variations Use less sugar for a more tart jam. If you add too little sugar the jam will go mouldy, if this happens scrape of the mould and reboil with additional sugar. One can also add lemon juice (to taste) to cut back some of the sugar.