Spicy Onion Mustard Relish Recipe


IMG_0018For the past several years there has been a lovely woman selling savory, artisanal jams at the farmers market. There is one of her flavors that I love the most. It is sweet and spicy onion jam, and I love it so much that at the end of each season, I buy at least six jars of it and horde it to last all winter.

Sadly, this year she is not at the market. Thus, I have no onion jam for my cheese plates and sandwiches. So what is a cook to do? Try to make it myself, of course.

And though I should have started my experiment small, I didn’t. I came home from the farmers market with about 20 pounds of onions, prepared to make this jam a dream come true.

To begin, I had to first slice the onions. That in and of itself was quite a task. To do it, I busted out my ski goggles. There is no good way to cut that many onions without a few tears, but doing it while wearing goggles solved that problem. While I looked ridiculous, and was thankful nobody stopped by during my chopping, it did the trick and not a tear was shed.

Using a mandolin for this step was another essential piece of equipment to the process. As long as you are careful to not cut yourself with the sharp blade, using a mandolin will ensure that every piece of onion is cut almost exactly the same size. This will create a consistency in the relish.

IMG_0016Now that that step was done, it was onto trying to make the jam. First, l looked at the ingredients on the last jar of onion jam that I have been saving. It seemed pretty straightforward: onions, sugar, vinegar, mustard seeds, red chili flakes. I then looked up some similar recipes online and got some ideas on how to make something similar. I decided I could do this just by estimating amounts.

Boy was I wrong. My “jam,” while delicious, is nothing like the one I like to buy. I have no idea how I got far off on the recipe, but once I got over the difference in taste, I stopped being disappointed. This onion relish is quite delicious. Though the ingredients are the same, my version is spicier, and is way more savory than sweet.

This relish would make a great gift at the holidays, or for any hostess or thank you present. I would serve it alongside a roasted piece of meat, on top of barbecue, and even, with cheese like the version I was trying to recreate.

Because there is vinegar and sugar, the recipe can be process and preserved into jars you don’t have to store in the refrigerator. You could half the recipe is you don’t want to make as much but I figure, why not just go all out and get a big batch over with all at once. Your friends will thank you at the holidays.

Spicy Onion Mustard Relish Recipe


  • ¼ cup of yellow mustard seeds
  • 2 tablespoons red pepper flakes
  • 2 tablespoons oil
  • 8 cups of onions, thinly sliced
  • 1 cup of apple cider vinegar
  • 1 cup of sugar


  • Heat a heavy bottom pan over medium high heat. Add the oil, then once it is warm, the mustard seeds and red chili flakes. Cook for about a minute or until the mustard starts to pop. Add the onions and cook, while stirring every couple of minutes, until the onions are wilted and starting to have a light brown color (about 30 minutes) turning down the heat to medium if the onions begin to get a color. Add the vinegar and sugar and stir to incorporate. Continue to cook for 5 to 10 minutes or until the sauce has started to thicken. Turn off the heat and let it sit until you are ready to process the relish in jars.


About Author

Mollie is a native Cape Codder who learned at an early age how to put a lobster to sleep, harvest cranberries, and dig for clams. After high school she followed her sense of adventure out west to the University of Wyoming where she graduated with marketing and communication degrees. She found herself making roots in Jackson, her fiance’s hometown, and using her sales skills combined with her love of anything delicious to join the Dishing sales team. She loves baking from scratch, large glasses of red wine, and hiking with her heeler, Newton. She’ll try anything, but remains a stuck up Cape Codder when it comes to seafood. If she didn’t catch it or see it come off the boat, don’t even try tempting her.

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