Preheat the oven to 200F.

Line a large, heavy baking tray with foil. This is important if you plan to make cherry bounce later, as it makes pouring off the fruit juice easier.

These cherries must be pitted. If you do not own a cherry pitter, this task can be accomplished using the flat side of a chef’s knife, with the blade facing away from you. Be warned that cherry juice will spray everywhere, and it stains. Wear an apron and old clothing. Avoid white curtains. Do pit on the baking tray, to catch all the precious juices.

Now pour the sugar over the cherries and tuck into the oven.

Bake, stirring the sugar periodically to ensure it dissolves. The cherries will dry up, wrinkle, and give off what seems enormous amounts of juice. This should take about two hours.

After about two hours, the cherries will look darker. The sugar will have completely dissolved. Don’t let the cherries or liquid burn. Lift tray out carefully to avoid spilling liquid.

What you do next depends on whether or not you intend to can.

Scenario #1: You are not canning:

Transfer cherries to a refrigerator-safe lidded storage vessel. Allow the fruit to cool a little before refrigerating no longer than five days.

Scenario #2: You are canning:

While the cherries bake, prepare your water bath canner.

Place canner on stove. Put the rack in. Fill to mark indicated on manual (I know, I said I hate this, but canners vary: on my canner, this is raised round band about four inches below the top). Turn the burner to low. This starts warming the water.

Sterilize three half-pint jars by washing them in hot, soapy water. Rinse well in hot water. I hold jars with tongs and run them under hottest tap. Dry either in dishwasher cycle or as I do, in the oven on lowest setting. I like to wash bands and lids, too, before placing them in a small pot of hot water.

Wash a ladle and funnel. Have white vinegar and clean rags or paper towels ready to wipe the jar rims.

When the cherries are finished baking, ladle them into the jars, leaving 1/2  inch headspace. See that glass band running around the top of the jar in my photos? That’s the 1/2 inch mark. In the photo, the middle jar isn’t filled to the 1/2 inch mark . You can get away with this, but an overfilled jar won’t seal properly. For more information on filling jars, see notes.

Wipe jar rims with rag or paper towels dipped in white vinegar. This cleans any drips and helps ensure a good seal.

Screw on the lids fingertip tight. “Fingertip tight” means you won’t need to call professional wrestlers to open your jars in three months. Place jars in waterbath. A tool called a jarlifter does this safely and cheaply. Put on the canner lid–something I often forgot in my early canning days–and crank up the heat. When the water reaches a full, rolling boil-you can peek–start timing. This jam needs 15 minutes. If you are a forgetful or distracted type, set a timer.

Once the 15 minutes are up, turn off the heat. Allow the jars to rest for 5 minutes, then remove them from the canner. Don’t leave them there for hours; they’ll overprocess.

It’s a good idea to place them on a wooden surface like a cutting board to cool. Don’t rest them on a cold surface: they’ll crack.

You’ll hear the lids go “thuck!” That’s a good noise. It means they’re sealing.

Allow your jars to cool at least 8 hours. Overnight is even better. Test seals by picking up jars with your fingertips, lids only. Lids should be firmly affixed.

If seals fail–you can get them off using just your hands, easily–you can reprocess, or refrigerate the jam. All will be well.

Notes: Cherries can be refrigerated 24 hours between baking and canning.

On filling jars: If you don’t have enough jam to fill the third jar more than halfway, refrigerate it. I have successfully canned jars that are half or three-quarters full. Don’t try below that. If you have 4 ounce jelly jars around, you can use those, but follow the 15 minute canning time. 

Jam is best eaten within a year, but will keep beyond that providing the seals are good. Cherries at the top may darken over time. That’s fine. They’re good to eat.

Obviously, if food shows any signs of spoilage–fizzing, discoloration, bad smells, throw it out.

To make this jam using strawberries: follow exactly, but bake for one hour, thirty minutes.