I have been swimming in plums recently. My friend Sarah’s tree started dropping ripe plums right before she went on vacation, so Sam and I went over and helped her clear out the branches. We were allowed to keep whatever we picked; within a few minutes we’d collected a paper grocery bag full of tiny red-fleshed fruit. The past couple weeks have been all about putting them to use.
A fair number of the plums got eaten straight from the bag, standing over the sink to catch the juices. I set a few aside for a cooking experiment I’ll write about later; a few more went into a riff on my favorite nectarine tart (verdict: plums need way more sugar than nectarines). That left me with about two pounds of quickly softening plums, a small canning pot, and–thanks to the BART shutdown–a lazy work-from-home afternoon. So I ignored the heat outside, turned on the oven, and made plum butter.
Fruit butters are a slightly different animal than jam–pureed smooth, softer and less jelly-like than jam, made for spreading rather than dolloping. Think applesauce, but richer, darker, thicker, in every way more so. The recipe I found calls for roasting, rather than boiling, the fruit; after an overnight soak in sugar and spices, the plums went into a heavy pot and then into the oven, where they slumped and wrinkled and filled my little apartment with hot syrupy perfume. From there, it was just a matter of pureeing the fruit to baby-food smoothness, and ladling it into hot prepared jars for the water bath.
In the jars, the plum butter is inky purple-black, the color of the blended-in skins; when I scraped up the dregs from the pot onto a spoon, it glowed translucent red. The flavor is concentrated plum, sweet from the flesh and tart from the skins, brightened with orange zest and prickly with cinnamon and cloves. I will be spreading it on popovers the first chance I get; I could easily imagine filling a cake or topping a scone with it, and even possibly using it as a sweet plum sauce on poultry. Well done, little plums. Well done.
Spiced Plum Butter (makes about 1 pint)
2 lb ripe plums (I used red plums), pitted and quartered
1 cup granulated sugar
1 tbsp lemon juice (about half a medium lemon’s worth)
1 (3 inch) strip orange zest
1 cinnamon stick
2 whole cloves
Special equipment: two half-pint canning jars OR four 4-oz canning jars
Combine all ingredients in a large mixing bowl (or a heavy oven-safe pot). Stir to combine, then cover and refrigerate for 8-12 hours (or overnight), or until the plums are starting to soften and the mixture is thick and syrupy.
Preheat the oven to 350º F. Transfer the plum mixture to a heavy oven-safe pot (or use the pot the plums macerated in). Bake for 2-3 hours, stirring every half hour or so, until the plums are very soft and the liquid is thick and jammy. Remove and discard the orange zest and spices. Transfer the plum mixture to a blender (or use an immersion blender) and puree until the consistency is as chunky or smooth as you want it.
Canning instructions: While the plum butter cooks, sterilize jars, lids, and rings. Transfer the hot pureed butter to the hot jars, leaving about 1/2 inch of headspace. Wipe rims, and apply lids and rings. Process in boiling water for 10 minutes. Sealed, cooled jars will keep for up to 8 months in a cool, dark place; once a jar is opened, keep it in the fridge and use within 3 weeks. (If you’re new to canning, there are detailed instructions here.)
Refrigerator/freezer instructions: Let the pureed butter cool for about 5 minutes, then transfer to clean jars, leaving about 1/2 inch of headspace. Wipe the rims, seal the jars, and let cool completely on the counter. Store the plum butter in the refrigerator for up to 3 weeks, or in the freezer for up to 4 months. Thaw freezer jam overnight in the refrigerator before using; once a jar is opened, refrigerate it and use it within a month.