Cooking

As someone with massive gut issues who also cannot handle onions or garlic I found Bell Peppers to be my newest favorite flavoring for dishes. Once you get the overwhelming taste of garlic/onion out of the way the pepper's complex flavors start to really shine through.

Also check out the Low FODMAP diet. Onions/Garlic are the main culprits to remove FODMAP from your diet and there are now lots of recipes available out there without them.

My partner had to eat low FODMAP for a few years but eventually their gut reset and now they can have small to moderate amounts of onions and garlic again. After the onion and garlic, the biggest hurdle to keeping low FODMAP is cutting out high fructose corn syrup because it's in so many packaged foods you wouldn't think about like certain brands of breadcrumbs (Progresso).

My number 1 suggestion is to make your own onion infused olive oil: put a roughly-chopped onion in a pot with a whole bottle of olive oil, warm it up (it should be warm not hot), let it cool, take out the onion pieces, and pour it back in the bottle (store in the fridge to preserve the flavor longer). You can do this for garlic as well but garlic-infused oils are a lot easier to find at the the store (just make sure you get infused oils that don't contain actual bits of garlic or juice, Boyajin was a brand I liked a lot).

I used to make fajitas without onions by using my infused oils in the marinade and upping the amount of bell pepper.

So you're just looking to replace the texture of both, not the flavors? It's not super clear what your partner isn't liking about them.

If it's just the texture, just chop them finer. For garlic, get a garlic press. If chunks of onion are an issue, heat them in oil, then remove the chunks before adding other ingredients to dishes. That imparts the onion flavor into the oil.

Sometimes issues with onions and garlic are due to allergies.

Some people are allergic to raw/undercooked onion, in which case you make sure to sautee and/or otherwise cook them through.

For garlic, some people are allergic to the sprout. You can kind of "core" garlic, slice it in half and dig out the central bit (which is what sprouts green), and typically it helps.

You could also try a different garlic variety, around here we also get Solo, which taste (slightly) different to garlic and don't seem to give the same problems with the sprout.

You can also try granulated onion and/or garlic.

If all else fails you can do infused oils, heat some oil with onion and/or garlic, strain and use as a flavouring agent.

(and of course you might try leek, spring onion, red onion. But I feel they're similar enough to only leave one disappointed about the real dish, rather than appreciating a "new take").

Maybe consider learning a cuisine that doesn't use onion and garlic as much, e.g. some Asian cuisine use spring onion instead, and the Japanese are very careful with garlic.

As for the texture, onion and garlic can be chopped very fine, and even grated for less texture.

For equal texture I'd actually suggest rethinking the sauce/dish. Don't do dishes that are centered around the onion texture (Chaliapin steak comes to mind) and you'll have a much better time. But: leek, kale, bok choi, wilted spinach, arugula/rocket, bean sprouts, etc all can do the slimy wrappy thing onion does, and even with a little chewyness with careful cooking.

But in a sauce you could just as well add small broccoli trees, finely chopped and/or sautéed cabbage, cauliflower, fresh herbs with sprigs (tender thyme sprigs are very nice, but also Basil, Mint, Coriander, Parsley, etc). If it gets too lumpy, you do a few pulses with a mixer and leave it at your desired texture (works great for both sauce and soup).

Cooking is a lovely expression of yourself and your care for others, and almost all situations can be solved with a little creativity (which of course is easier crowd sourced). I hope you find some inspiration, and I wish you both the best of luck on this endeavour.

Can't help you with replacing the texture, but I have gotten shallot infused olive oil for imparting the flavor. They also have garlic oil, of course.

It's the onion solids that offend most people, and often when thoroughly cooked, the proteins are denatured(?) enough to not cause me issues.

Raw onion and onion powder will mess up my system.

My kids who hate cooked onion love fennel. Whole different flavor profile but oddly not a bad substitute, agree with you. Shallot they also like, if that works the flavor is much closer, but if all alliums are out, it's out too.

ETA: Indian food sometimes has asafetida instead of garlic.

I think if I was going for no alliums at all, I'd look for replacements for each use of them vs a blanket substitute.

You mentioned fennel as a good substitute, but the anise flavor isn't right in some applications. When caramelized, that anise flavor mellows out, so it works really well as a substitute for caramelized onion.

In a more lightly cooked application, like a stir fry, you might want to get a similar texture with cabbage. Sauer kraut (and its asian relatives like kimchi) is good for a "sharper" taste.

For pickled onions, you can replace with pretty much anything else pickled.

For texture you could use finely chopped celery.

Shallot is the usual onion substitute. But it being in the same plant family, I'd guess makes it not a good option?

As a flavouring there are a number of things you can use. Flavoured oils are the easiest to use/find but don't give a ton of flavour. I also find a lot of them taste pretty bad, Colavita garlic olive oil is the only one I buy. FreeFod makes FODMAP free onion and garlic powders that work a treat. Otherwise I mostly use a lot of green onion tops when I want onion flavour.

I normally don't have too many issues with the texture side, what kind of dishes does removing the onion cause problems? If you are blending the sauce and the onion is adding body, maybe look at different thickening options like xanthan gum.

Lastly, Fodzyme makes a enzyme powder that works against various FODMAPs including Garlic and Onion. Its expensive, but worth it for eating out or the dish doesn't work without the onion/garlic base.

For garlic you could try Ramson.

My partner does not like sliced onions, but is fine with onion powder. Same with garlic. So I just put in the powder for the flavor and less chopping. 😀

I hate the texture of onions and don't like strong oniony flavor. We use dried onion flakes. You have a lot of control over how much flavor there is and the texture is gone.