There's such a bounty of sun-ripened fruit at the end of the summer that it can be overwhelming. Peaches, nectarines, plums, figs, some late berries - often overripe yet full of the sweetness of the summer. If you want to hold on to that summer goodness for a little longer, buy some bruised fruit (probably on sale) and cook a quick jar of jam.
Jam looks intimidating - boiling and canning and sterilizing and botulism all rolled into one specter of potential food poisoning. But while canning itself is much easier than it looks, you don't need to mess with that for just one or two quick jars of jam. An hour or two will give you a jar of jam that can be frozen for up to six months or refrigerated for a month with that taste of summer fruit locked inside.
Recipe for plum cinnamon jam below...
This basic recipe can be applied to almost any fruit. Plums have a lot of natural pectin, so this will be a jammy jam. Other types of fruit probably won't get as firm as jams you buy from the store, but even runny they will be delicious on toast, in yogurt, or smeared over a cake.
Put a ceramic saucer in the freezer. Pit and quarter the plums. Measure the fruit, then measure out 3/4 cup sugar for each cup of fruit. Layer the plums and sugar in a large heavy pot with high sides. Put in the cinnamon stick, juice of one lemon, and about half a cup of water.
Bring to a simmer slowly, stirring. Stir until the sugar has been completely dissolved. Simmer over low heat for about 10 minutes, or until plums are softened.
Turn the heat to high and bring to a hard boil. Boil for about seven or eight minutes. If you have a candy thermometer, you're watching for the temperature to go over 200°F.
When it has been boiling about eight minutes, take a saucer from the freezer and dribble some jam on it. If it sets with a thin gel coating immediately forming as it cools, preventing the jam from running all over the plate when tipped to the side, then the jam is ready. Take off the heat, pour into clean jars and let cool. (If the jam does not set after eight minutes, boil for a minute or two longer. Don't let it boil too long; if it does it will caramelize and get very dark, destroying the flavor of the fruit and basically becoming not very good to eat. Runny jam is better than overcooked sludge.)
Remove the cinnamon stick and store in clean washed jars or a glass bowl with a lid. This will keep for at least a month in the fridge.