A week or so ago, I was bemoaning my lack of plums. I used to rent a house with the most gloriously productive Santa Rosa plum tree you could imagine. During my first two summers of canning, I picked and jammed so many plums that I thought I would never want to see a plum again. Not so. After moving out of that house and passing a couple of plumless years, I found myself longing for that old tree.

So far, my search for a new source of free, backyard Santa Rosa plums has been– well — fruitless. But what about the legions of little red and yellow plums dropping off trees in every other yard and sliming sidewalks from one end of town to the other? Do you have plums like that where you are? Have you tasted them? Some of them are really good.

I went looking and found rogue plum trees in vacant lots and around the shaggy edges of parks. I found them hanging over fences, where they dropped their unwanted fruit on my shoes. I started picking. And I had help. Here’s a text exchange with a good friend, who shall remain anonymous lest she be nabbed by the neighborhood plum police . . .

I don’t want to know exactly how she did it, but a day or so after our conversation, she presented me with a bag of red jewels. I mixed those plums with fruit from two other trees to make neighborhood plum jam.

This recipe is different from the ones I usually post. The ingredients are simple — plums, sugar, lemon juice, a bit of optional booze — and the process is easy. That said, the precise measurements depend on how many plums you glean and on your own taste, so what I’m going to do is try to provide some basic instructions for building your own jam. (For inspiring some of the underlying methods, I’m grateful for the beautiful Blue Chair Jam Cookbook, by Rachel Saunders.)

Neighborhood Plum Jam

3 – 6 pounds of pitted, chopped plums (I used 5 1/2 pounds)

sugar (I used 3 1/2 pounds)

lemon juice (I used 3 ounces; you’ll want to use at least 2)

bourbon, brandy, or other boozy add-in (optional)

Step 1: Determine the Quantities of Your Plums and Sugar

1. Begin by pitting and then weighing your plums. These little guys weren’t very willing to separate from their pits, so I used a sharp knife to cut away as much flesh as I could. Weigh your plums after you pit them, but consider this twist: Because the plums are small and the ratio of skin to flesh is high, I put about a third of my plums through a food mill before weighing. (I wanted my jam to be tart, but not as tart as all of that skin would likely make it.) I composted the skins caught in the mill, mixed the resulting pulp together with the rest of the chopped plums, and weighed that. I found that I had 5 1/2 pounds of plum stuff in my bowl.

2. Decide how much sugar you want to use. I suggest an amount that is 50%-70% of the total weight of your plums. My plums were a bit tart, so I decided to go for about 65% sugar, and I love how it turned out. First, I converted the weight of my plums to ounces: 5 1/2 pounds of plums equals 88 ounces. I multiplied 88 by .65 to determine that 65% sugar would be roughly 57 ounces, or about 3 1/2 pounds. Are you with me? (I’m actually not very good at these kinds of calculations and often have to ask Stewart for help.) You can fudge the numbers a little bit one way or the other. It will be okay.

Step 2: Let the Plums and Sugar Get Acquainted

Combine the sugar and chopped plums in a big glass or ceramic bowl, cover the bowl tightly, and let it rest in the refrigerator for 12-24 hours.

Step 3. Make Jam

1. Prepare your jars (they’ll need to be hot but not necessarily sterilized, because the processing time is 10 minutes) and put 5 metal teaspoons on a plate in the freezer to test your jam for doneness later.

2. Stir 2 ounces of lemon juice into the plum mixture. Taste it. You should be able to detect the juice, but just a hint of it. If you don’t taste any lemon, stir in a little more juice until you reach the level you like. (Add the juice just a little at a time. Too much will create a burn on the tongue and, like salt, you can’t take it back.)

3. Transfer the mixture to an appropriately sized jam pan and bring it to a boil, stirring frequently. Cook the jam at a steady boil, monitoring it carefully and stirring enough to prevent sticking or scorching. As the jam cooks, skim the foam with a large, shallow, stainless-steel spoon. Turn down the heat as moisture evaporates and expect to be stirring the jam slowly and almost constantly for the last 10 minutes or so of cooking time. My jam, cooked in an 11-quart pan, was done in about 35 minutes, but your cooking time will depend on many factors, including the amount of fruit, the size of your pan, and the heat of your stove. Test the jam for doneness when it has thickened, the foam has settled down, and the bubbles are small and shiny.

To test your jam for doneness: Remove the mixture from the heat. Use one of your frozen spoons to scoop up a little bit of jam — not a whole spoonful. Return the spoon to the freezer and wait 3 minutes. Retrieve the spoon and hold it vertically. If the mixture looks almost like it wants to run, but can’t, and it has substantially thickened, it’s done. Alternately, give the mixture a little push with your finger. If you see creases or wrinkles, it’s ready. If the jam runs, cook it for 2-3 minutes more (stirring all the while) then test again.

4. Remove the jam from the heat and skim any remaining foam. If you’re inclined to stir in a splash of something — a couple tablespoons of bourbon or brandy — now would be the time.

5. Pour the jam into hot jars, leaving 1/4-inch head space. Wipe the rims clean, apply the two-piece lids, and process in a hot water bath for 10 minutes, adding time for your elevation if necessary.