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Low FODMAP caramelised onion

Much like my roasted pickled garlic recipe, this low FODMAP caramelised onion recipe is one of my absolute favourites to date. In developing my low FODMAP pickled garlic, I realised that pickled onion has had a low FODMAP threshold for a while now. With that in mind, I knew I had to make some low FODMAP caramelised onion using pickled onion.

Low FODMAP caramelised onion

Of course, this recipe uses pickled onion instead of regular onion to remain low FODMAP. Onion is generally high FODMAP irrespective of the serving size, but pickled onion is low FODMAP in 45g serves.

Using pickled onion is as easy as using regular onion. To start, we give the pickled onion a quick rinse to remove any excess vinegar tang. I prefer to use my own pickled onion recipe here as I have designed it to be ‘bland’ (ie focused on the onion flavour rather than adding extra flavours like herbs).

Next, we simply cook the onion in a pan with oil and maple syrup (for caramel sweetness but also to counteract the pickled tang). Over time the onion becomes shrivelled, browned and caramelised. Perfection!

This recipe couldn’t be easier! It can easily be made in a smaller, separate pan at the same time as caramelising onion for the normies. This way, everyone gets to enjoy the deliciousness of caramelised onion.

An aerial image of caramelised pickled onion in a black frypan

FODMAP notes

As we have discussed, pickled onion is low FODMAP in 45g serves. Monash hasn’t specified an upper or lower limit or what the predominant FODMAP might be. Raw onions contain fructans, but so does raw garlic and yet pickled garlic (in moderate serves) contains fructose.

You can scale this recipe up as you see fit. I probably wouldn’t recommend scaling down, as I worry that there would not be enough onion to caramelise easily.

Maple syrup is low FODMAP in 50g serves (2 tablespoons per person). This recipe only uses 1 – 1 1/2 and serves four people.

Other than that, we’re golden! Oil is a no FODMAP food, as is salt.

How much does this recipe make?

This recipe serves 4 people. 45g of pickled onion is a decent serving size raw, but it does definitely shrink down once caramelised. My estimate is that you will get about 1 Australian tablespoon (4 teaspoons elsewhere). So, not a super generous serve.

With that said, 1 tablespoon of caramelised onion on a burger is a hell of a lot better than no caramelised onion! It’s about being able to enjoy something delicious, not necessarily a huge serving size.

I find it also helps to use the caramelised onion in a recipe as opposed to on its own. For example: my upcoming low FODMAP French onion dip or my low FODMAP caramelised onion pasta. Both of these recipes make the most of the caramelised onion flavour and still divide them into the appropriate serving sizes.

Recipe tips for your low FODMAP caramelised onion

  • The cut of your onion will depend on whether you are making your own pickles and what you’re using the caramelised onion for. If you make your own pickled onion, you get to slice the onion the way you like. If you buy them, you have to work with what you have.
  • I like to caramelise thin onion rings for a standalone caramelised onion. If I’m making it for a dip, I like chopped caramelised onion. Make sure, whatever you do, the onion pieces are thin. This will give you maximum caramelisation.
  • You can chop your pickled onion before or after caramelising (I’d say go before, but you can always chop after if you change your mind). If you chop after, I find it easier to use scissors.
  • If you are buying pickled onion, make sure it doesn’t contain any high FODMAP ingredients. Currently, I would say that quick pickles are not appropriate for this recipe nor would logic suggest they are low FODMAP. If and when Monash clarifies this, I will update the post.
  • I found this took about 20-30 minutes of cooking time to reach a good level of caramelisation. I also find that is helps to add water every time they start to stick. This helps create a soft and malleable textured pickled onion. We don’t want them to be dry!
  • You can use whichever variety of onion you like – I prefer Spanish/brown onions. They look lovely and golden brown and their flavour profile matches what I’m looking for in a caramelised onion.
  • You can use butter in place of the oil, if you fancy it.
A brightly lit aerial image of a frypan filled with low FODMAP caramelised pickled onion. The frypan sits on a reddy grey backdrop and two sunlit glasses of water sit in the top left of the image

More low FODMAP recipes

An aerial image of a small white ceramic bowl filled with low FODMAP caramelised onion. The bowl sits atop a medium reddy grey backdrop and two sunlit glasses of water sit in the top left corner of the image, creating light and shadow patterns across the onions

Low FODMAP caramelised onion

Vegan, gluten free
*Cups and measures are in Australian cups and measures. Use gram and ml for international accuracy.
This recipe assumes you are using pickled onions without any high FODMAP ingredients added or any bold ingredients that might change the flavour profile.
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Prep Time 5 minutes
Cook Time 25 minutes
Course Condiment, Seasoning, Side Dish
Cuisine Food Intolerance Friendly
Servings 4 people


  • 180 g pickled onion (see notes)
  • 20-40ml (1 – 2 tablespoons)* oil of your choice (you can also use butter)
  • 20-30ml (1 1 1/2 tablespoons)* maple syrup
  • 250ml-375ml (1 – 1 1/2 cups)* water
  • Fine salt, to taste


  • Rinse your pickled onions to remove any excess vinegar. Pat dry.
  • Heat your oil in a saucepan over a medium heat. Once shimmering, add the pickled onion and a small pinch of salt and stir to coat the onion in the oil.
  • Once the onion starts to get a little bit of colour, add 20ml (1 Australian tablespoon or 4 teaspoons elsewhere) of maple syrup and turn the heat down.
  • Add a splash of water whenever necessary – this is critical for soft and creamy caramelised onions. I keep my measured water out by the stove and add a splash any time they are looking dry. You don't have to use it all, but have it on hand.
  • Continue to cook for about 20-30 minutes or until your onions are golden brown. Add the remaining maple syrup and stir until glossy and soft. Season to your tastes.
  • Because this makes a small batch, I doubt there will be leftovers. If there are, store them in an airtight container in the fridge and use within a few days.
  • Each serve is about 1 Australian tablespoon (4 teaspoons elsewhere). Small, but still delicious. If Monash ever updates the entry with a higher threshold, I will change the recipe in a flash.


  • As mentioned in the post, Monash has large pickled onions listed as low FODMAP in 45g per serve. They specify that small pickled onions (cocktail onions) have no low FODMAP threshold.
  • Monash has not provided us with an upper limit for pickled onions. With that in mind, I recommend sticking to the 45g for now. You can always test your own tolerance if you’re up for the challenge.
  • Monash have also not yet specified if quick pickles have a low FODMAP threshold, but in the meantime they are not suitable for this recipe. Store bought or homemade refrigerator pickles are used here. 
  • If you are using store bought pickled onion, make sure it doesn’t contain any high FODMAP ingredients or any bold flavours that will disguise your onion. My recipe for pickled onion can be found here
  • It can be tricky to only eat one serve of these, but try to resist if you know it will cause you issues!
  • Each serve once caramelised is small – about 1 Australian tablespoon (4 teaspoons elsewhere). The perfect quantity to top a burger or to use in a recipe for flavour. I will be posting plenty of caramelised pickled onion recipes soon.
  • I have made a batch where I weighed the onions straight from the container and one where I thoroughly squeezed out the excess liquid before weighing. I suspect the latter is cheating on the FODMAP principle, but it’s open to your tolerances. In the batch where I squeezed them before weighed (and then used approximately 375ml water during cooking) I got 110g of caramelised onion. 
Keyword Caramelised pickled onion, Low FODMAP caramelised onion, Low FODMAP pickled onion
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