CanningCraft Creates: Caramelized Onion-Maple Jam

Allison Carroll Duffy

Allison Carroll Duffy

Oh, I think I have found a new favorite condiment!

Loaded with caramelized onions, and sweetened with maple syrup and apple cider, this soft-set jam is rich, earthy, and complex. It has quickly become my go-to jam for dressing up a cheese plate, and it’s delicious alongside roast turkey or roast pork, so it’s perfect for the holiday season.

This jam doesn’t contain many ingredients, so quality is key. Be sure to use 100 percent real maple syrup, and use fresh apple cider if you can get it. Apple juice will do in a pinch, but cider is better, as it’s sweeter, richer, and has a more complex flavor.

The other key to success with this recipe is technique — which is not something I say about very many recipes. The deliciousness of this jam is due largely to the successful caramelization of the onions, as well as the concentration of flavors by cooking down the jam to reduce the liquid content. Neither of these things are difficult to do (so in case you are worried, please don’t be!), but a little attention to detail will go a long way, especially in step 3.

Most of us are used to caramelizing onions in fat such as butter or oil, but this recipe, as it is designed to be a can-able recipe, calls for caramelizing the onions without any fat, so the process is a little bit different.

crackers, cheese, onion jamCaramelized Onion-Maple Jam

Yield: 4 to 5 cups

Before You Begin:
Prepare calcium water. To do this, combine ½ teaspoon calcium powder (in the small packet in your box of Pomona’s pectin) with ½ cup water in a small, clear jar with a lid. Shake well. Extra calcium water should be stored in the refrigerator for future use.

Caramelized Onion-Maple Jam Ingredients

2 pounds onions (6 cups sliced)
1 teaspoon salt
3 cups apple cider
1 cup plus 2 tablespoons apple cider vinegar (5% acidity)
¼ teaspoon black pepper
2 teaspoons calcium water
1 cup maple syrup
2 teaspoons Pomona’s pectin powder

Caramelized Onion-Maple Jam Directions

1. Wash and rinse jars, lids, and screw bands. Set screw bands aside until ready to use. Place jars in boiling water bath canner with a rack, fill at least 2/3 of the way full with water, and bring to a boil. Boil jars for 10 minutes to sterilize (add 1 additional minute of sterilizing time for every 1000 feet above sea level), then turn down heat and let jars stand in hot water until ready to use. Place lids in water in a small pan, bring to a low simmer, and hold there until ready to use.

2. Peel the onions and discard the skins. Slice the onions very thinly, and then cut the thin slices into approximately one-inch lengths. Place sliced onions in a sauce pan – ideally, a heavy-bottomed one that conducts heat evenly. Add the salt, then mix.

sliced and cut onions

Sliced and Cut Onions

3. Put the pan on the stove, cover the pan with a lid, and cook the onions over medium to medium-low heat for about 5 minutes. While the onions are cooking, occasionally lift the lid and give the onions a quick stir to be sure that they are not starting to burn. If they are, reduce the heat slightly, replace the lid as quickly as possible, and keep cooking. If the onions are really sticking, you may add a very tiny bit of the apple cider to ease the sticking, but only do this if it’s really necessary.

After 5 minutes or so, the onions should have caramelized a good bit, and should begin to have a nice golden-brown color. If not, cook the onions for a little bit longer, with the lid still on, to achieve this. At this point, when the onions have really started to brown, they’ll probably want to start sticking. So, remove the lid, reduce the heat if necessary, and stir constantly, scraping off and incorporating the brown bits on the bottom of the pot as necessary for a couple more minutes. This will allow the onions to continue to brown and caramelize while preventing burning.

caramelized onion in pan

Caramelized Onion in the Pan

4. After the onions are caramelized and well-browned, add the apple cider, the vinegar, and the pepper to the onions. Increase the heat and bring the mixture up to a boil. Cook the mixture at a low boil for a couple of minutes, stirring frequently, to allow the liquid to reduce in volume.

5. Remove the pan from the heat, then measure the mixture. (A large-capacity, heat-tolerant measuring container works well for this, as it allows you to transfer the mixture from the pan directly into the measuring container). If the quantity of the mixture is more than 4 cups, place the mixture back in the pan and allow it to continue cooking until you have reduced the quantity to 4 cups, measuring as necessary to confirm quantity. If you find that you have less than 4 cups, add a small, additional amount of apple cider to bring the total quantity of the mixture back up to 4 cups. Transfer the onion mixture back into the sauce pan, add calcium water, and then stir to combine.

6. In a separate bowl, combine the maple syrup and pectin powder. Mix well and set aside.

maple syrup and Pomona's pectin powder

7. Bring the onion mixture to full boil over high heat. Add the maple syrup-pectin mixture, and then stir vigorously for 1 to 2 minutes, still over the highest heat, to dissolve pectin. Return the jam to a boil, and then remove from heat.

8. Remove hot jars from canner and fill jars with preserves, leaving ¼ inch of headspace. Remove trapped air bubbles, wipe rims with a damp cloth, and put on lids and screw bands, tightening bands only to “fingertip tight” (until resistance is met, and then just the tiniest bit more).

9. Place jars in the hot water, on the rack inside the canner. (Make sure jars are upright, not touching each other or the sides of the canner, and are covered with at least 1-2 inches of water). Place the lid on the canner, return the canner to a rolling boil, and boil for 10 minutes. (Add 1 minute additional processing time for every 1000 feet above sea level.)

10. Turn off heat and allow canner and jars to sit for 5 minutes. Then remove jars from canner.

11. Allow jars to cool undisturbed for 12 to 24 hours. Then confirm that jars have sealed. Remove screw bands from sealed jars, rinse off outside of jars if necessary, label jars, and store for later use.

jam on spoon in and in jar

Recipe and photos by Allison Carroll Duffy

Printable copy of the Caramelized Onion-Maple Jam only here.

6 thoughts on “CanningCraft Creates: Caramelized Onion-Maple Jam

  1. I used a heavy-bottomed Dutch oven, and it took close to 45 minutes for the onions to brown, but I think that was due to scraping up as much of the fond as I could. I followed the directions to the letter, and sliced the onions thin. I worried about the onions not browning, but the end result was quite yummy. I’m going to make it again for holiday gifts.

  2. Hi Mary Lou, Allison and Bob. I had the same experience as Bob. My onions eventually went brownish after nearly two hours, an hour and a half of that steaming and staying white. That’s when I added half a teaspoon of sugar. By the time they started to change colour, the pan (stainless steel, heavy bottomed) was getting very burnt so I did deglaze with cider, but not before the hour and a half steaming and fifteen minutes with the sugar. Of course after all that time the onions were almost a puree. The finished product tastes good, if a little vinegary. Some recipes for preserves with vinegar recommend leaving to “mellow” for three months, what do you think? As for the caramelising question, I think onions probably vary in sugar and water content. It’s all an interesting challenge 🙂

    • Dear Paula,
      Thanks very much for writing to us about your experience with the Caramelized Onion-Maple Jam. I’m thinking you’re on to something about the differences in water and sugar content in onions. That is a helpful observation!

      I’m sorry this didn’t work out by the directions for you, but your idea of adding a little sugar was also a good one and I’m glad the final taste is good.

      I emailed Allison for her response and this is what she said: ” As for the differing sugar and water content in onions, that is very likely true. Too bad it is very difficult to assess the sugar and water content of a particular onion! Her idea is a good one….this might account for the difficulty she and Bob had with getting the onion to caramelize.”

      In regard to the 3 months of “mellowing,” it is not something Allison has heard of.

      I also asked my sister Connie, who has more experience than I do, about the mellowing idea. Her response: “I have never heard of vinegar jams & jellies needing 3 months of mellowing. I don’t think that having the sealed jars sit for 3 months before opening would make much difference in the taste!

      “I found a reference on the internet about making mustard and the blogger talked about the first tastes of the mustard being very sharp so she was looking forward to tasting it daily to see how it mellows. I think this is different from a jam or jelly with vinegar in it which I would not expect to mellow.”

      Unfortunately, we don’t have any definitive experience on the topic of mellowing jams/jellies with vinegar. Would be interested to know if you find a change if you do open a jar after 3 months!

      Thanks for using Pomona’s — and happy jamming!

    • Hi Bob,
      I’m very sorry you had such a difficult time with the Caramelized Onion-Maple Jam recipe, but I’m glad it at least tastes good! I think it’s likely how thin the onions are cut and the type of pan you use could make a difference in the browning process.

      I asked Allison for her thoughts and she said: “I’m sorry Bob did not have success with the onion jam. I don’t really know of course, but I’m wondering if he may have added water to the onions? I say in the recipe that you could add a tiny bit, but it’s possible he might have added too much. I’m guessing this because if he didn’t add water, and cooked them for a long time, seems like they would have burned. It’s true that if you add too much water they definitely won’t caramelize. It is a bit tricky, getting them to caramelize when there is no oil, and I was hoping my more detailed directions would help with that. Anyway, I’m sorry this happened to him.”

      Bob, thanks for using Pomona’s Pectin. I hope we’ve provided some insights for you.

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