I can’t give any one source the full credit for inspiring me to make this. I’ve seen onion jams on grocery store shelves since my first night in Cambridge, and I had some tasty onion chutney on an ostrich burger at the Market Square. Like most things I make, though, there was a definite catalyst that got me to actually do it. In this case, it was a recent post on Smitten Kitchen: squash toasts with ricotta and cider vinegar. Basically, you roast butternut squash, reduce some cider vinegar and maple syrup with sauteed onions, put it all on freshly-toasted bread, and top with mint. It sounds absolutely amazing. What my weird little brain got out of it was, “Hey, that onion thing sounds like the beginnings of a chutney/jam/relish!”
So I decided, to hell with all the obviously good ingredients for a change. I mean, I love winter squash, I love ricotta, and I will sing the praises of toasted artisan bread for any meal. But I think I take onions for granted most of the time. They’re the first ingredient in almost every savory dish I make, but they’re usually providing a base flavor for the more glamorous ingredients to dance on top of. If each meal were a rock band, the onions would the bass player, or maybe the drummer.
Anyway, I decided that caramelizing the onions was the way to go for this recipe. I’d never actually done it before (intentionally, at least), and, based on my experience making this, I probably won’t do it very often, because it takes a really long time. However, caramelized onions are absolutely delicious, and they made this relish* totally awesome. If you want to know how to caramelize onions, The Kitchn has a pretty detailed guide. I swapped the maple syrup in the original recipe for honey, because maple syrup is crazy expensive in the UK, but I’m pretty sure it would be even better with that extra maple flavor. To compensate and give it a bit of a spicy kick, I added some mustard and dried chili flakes and hoped it wouldn’t overpower the other flavors.
Turns out I was underestimating the power of onions! The flavors turned out very well balanced indeed (at least in my opinion…but then, most of these ingredients are ones I would gladly eat/drink plain in small quantities). I definitely want to make this again in a larger batch, which is more practical given the long cooking time. The flavors got even better over the next few days, so I’d imagine that this would be a good recipe to seal in jars, like you would for jam, and let age for a while. I haven’t put instructions up for that because I’m not personally confident in my jarring skills, but there are plenty of resources on the internet to help you there.
*I kind of hate using the word “relish” for this because I can only picture the unnaturally green stuff that comes in a BBQ three-pack from Costco with ketchup and yellow mustard and always ends up totally untouched at the end of your grill party. However, it feels wrong calling this “jam” because it contains no thickener. I guess it could be “European-style chutney,” but I’ve had onion versions of that, and they’re significantly “jammier” than this. So I’ll get over my dislike of the word in the interest of precision of nomenclature.
Caramelized Onion Relish
Adapted from Smitten Kitchen.
Yield: ~1/2 cup. (Scale up!)
2 small yellow onions
1-2 Tbsp olive oil
1/4 c apple cider vinegar
3 Tbsp honey or maple syrup
1-2 tsp wholegrain mustard
1/4 tsp dried chili flakes (or more to taste)
Peel onions, halve lengthwise (that is, cutting from root to stem end), and slice into thin half-rounds. Using medium heat, warm oil in a medium skillet or frying pan (ideally large enough for your onions to just be a thin layer across the bottom, not piled high on each other). Add onions, stir to coat with oil, and cook, stirring occasionally and scraping the bottom of the pan when necessary, until soft and brown, about 40 minutes.
When onions are caramelized, give the pan a final stir and scrape, then add apple cider vinegar, honey or maple syrup, mustard, and chili flakes. Scrape the pan to release the stuck-on goodness and stir to combine all ingredients well. Let mixture reduce, stirring occasionally, until liquid is almost gone and everything is a rich brown color and slightly jammy in consistency. Remove from heat and transfer to jars, storage containers for the fridge, or a serving container.
Serving suggestion: on toast with cheese and tomato, alongside scrambled eggs, topping grilled or pan-fried sausages, on sandwiches, in savory oatmeal with black pepper, parmesan, and tomatoes, or however you like it!