The best plum jam recipe is also the easiest to make

For the past five years, I’ve spent my late-summer birthday making plum jam. Parties are fun. Cake is good. But all I want is the quiet pleasure of standing over the stove, stirring and staring as the violet fruit transforms from thin, bursting bubbles to slow lava pops.

And at the end, I get the best jam that I can’t buy in any store. I keep big plum chunks in a base just a little less runny than honey. It swirls beautifully into yogurt or oatmeal and, of course, it’s awesome on toast. It drips into the crags of rustic loaves, soaks a little into milk bread. It gives you the PB&J of your dreams. Spooned over ricotta on brioche? You’re living the L.A. dream of brunching at Sqirl — without waiting in line — feeling like maybe you can be as cool as chef Jessica Koslow.

To achieve this plum jam nirvana, start with good fruit. It doesn’t have to be precious stuff — save that for eating fresh — but find fragrant plums and pluots. That’s obvious. This next trick, less so. Start by cooking down the fruit before adding the sugar. It intensifies the fruit’s flavor and prevents the sugar from overcooking into unwelcome burnt bitterness. Once the sugar goes in, it liquefies into the plums’ juices and caramelizes just enough to deepen the plummy-ness while keeping the flavor fresh.

While you can jar the jam to make it shelf-stable, it’s easier to keep it in the fridge. Once chilled, it’s best within a few weeks, but it’ll definitely be gone by then.

Canning jars are ideal for storing homemade jam.

(Leslie Grow / For The Times)

Birthday Plum Jam

30 minutes, plus cooling. Makes about 3 half-pint jars.

Lemon juice accentuates plums’ tart side and adds natural pectin, which helps the jam set. You can skip it if you prefer a purely sweet and runny jam. The timing on the jam will depend on how ripe and juicy the fruit are. Follow the testing technique below to stop cooking at the right time.

Ingredients

• 2 pounds plums and pluots, pitted and cut into ½-inch dice (3 ½ cups)
• 1 tablespoon fresh lemon juice
• ½ teaspoon kosher salt
• 2 cups granulated sugar

Instructions

1. Put 3 metal spoons in the freezer. Combine the plums, lemon juice, salt and 1 tablespoon water in a medium saucepan. Bring to a simmer over medium heat, stirring occasionally. Reduce the heat to medium-low and simmer, stirring occasionally, until the fruit starts to soften a little, about 3 minutes.
2. Stir in the sugar. Bring the mixture to a boil over medium-high heat, stirring occasionally. Reduce the heat to maintain a steady low boil. Continue boiling, stirring and skimming off foam from the surface occasionally, until the mixture is thickened and drizzly like maple syrup, 12 to 15 minutes. To test the jam’s doneness, take a spoon from the freezer and scoop a little onto the tip. Tilt the spoon; the jam should glide as slow as honey. Repeat the testing with the remaining spoons if needed.
3. Divide the jam among three clean half-pint canning jars. Seal and cool to room temperature, then refrigerate.

Variations

Star Anise Plum Jam
Add 3 whole star anise to the saucepan with the plums in Step 1. You can jar the jam with the star anise, but discard before eating.

Spicy Plum Jam
Add 1 fresh seeded and minced habanero or Scotch bonnet chile pepper to the saucepan with the plums in Step 1.

Make ahead
The jam can be refrigerated for up to 2 weeks.