The LH diet can be make it extremely challenging to eat well, since a lot of the foods many people rely on to make their cooking "pop" are full of histamine. It doesn't help that these foods are very hard to avoid in pre-made foods available at the shops - almost every shop-bought stock cube, for example, will have tomato and celery in it (two foods that are absolutely chock-full of histamine). When you get down to the foods that not all people who need to eat LH don't tolerate, it gets even harder: I can't eat sunflower safely, and sunflower oil is pretty much everywhere in processed foods.
Figuring out what won't make you ill to eat is one thing, but making your food actually taste good is another entirely. For a comprehensive look at what makes for a delicious, well balanced meal, I'd recommend getting a copy of Salt, Fat, Acid, Heat, by Samin Nosrat. If you'd rather not buy it or ask for it at your library, the title already tells you a lot of what you need to know. Salt, fat, acid, and heat (referring to both spicy-ness and temperature) are what Nosrat believes make up the bones of a solid meal - and I agree with her! The problem people often have with LH is that, if you can't tolerate citrus fruit, vinegar, seafood, or anything fermented, the "easy" (well-trodden) paths to flavourful food aren't any option anymore. But that doesn't mean you have to eat plain mashed potato for every meal! You just need to be willing to get creative with where you get your salt, fat, acid, and heat from.
This section of The Low Histamine Kitchen covers hints and tips for adapting recipes to LH without compromising on flavour, as well as recomemndations for LH shop-bought foods, and some not-quite-recipes you can use for substituting high histamine salt, fat, acid, and heat.
Not being able to use lemon juice or vinegar in recipes can leave food feeling a bit flat. Acids bring out other flavours, and the zing is much missed if not included in a recipe that calls for it. It took me a while to find LH foods I could use for that purpose, but I found two in the end!
While not strictly a one-for-one vinegar substitute, pomegranate molasses is really a really useful sweet acid. The taste is complex, sweet and tart and a little bit bitter. It's great in salads as a dressing, and can make a great glaze for meat or roast veggies. I've even used it in place of vinegar in gluten-free bread baking, where it produces a slightly pink loaf with a complex and delicious flavour.
Malic acid is usually derived from apples, since it's what gives green apples their tartness. If you can't tolerate apples, it's still worth testing malic acid out - I can't tolerate apples, but have no problem with malic acid. Buy it in powder form, and disolve a small amount - you don't need much, barely the tip of a teaspoon - into 30ml of water. Give it a taste: it's as close to lemon juice as I reckon you can get with LH. Try it in any recipe that calls for lemon juice, including in emulsions where it can act as the necessary acid component.
It won't always be possible to make a recipe work with LH ingredients. There are some things that are some ingredients that a dish just won't work without. Chilis, for example: there is no way to access spicy heat on LH, and if a dish revolves around that spicy heat, reproducing it without it is going to be plain depressing. If you're trying to adapt a recipe, but you're getting to a point where more than half of the original ingredients are being replaced with things that bear no resemblence to them, it's probably time to move on to a different recipe.
All that being said, though, there are still plenty of ways to adapt a lot of your old favourite recipes for LH. The key to doing so is to understand the role that each ingredient plays in the flavour and texture of a dish, and to know what you can eat safely.
Let's say you want to adapt mac and cheese to be LH, something pretty simple. There are a lot of things you need to know about what you can tolerate first: whether you can eat gluten (what gf pastas can you tolerate? Are there specific ingredients in gf things you can't tolerate, like corn?), whether you can tolerate dairy (can you tolerate soft cheeses, but not aged hard ones? Are you totally dairy free? What dairy alternatives can you tolerate? Would you consider making your own substitute cheese, out of a tolerated nut or milk?). Once you know all that, you can look at what makes up mac and cheese, and how you can replicate it with ingredients you can tolerate. Coconut milk, thickened with agar agar, and flavoured with seasonings (check out my accidentally LH page for the recipe) can be a very convincing cheese substitute. A shop-bought rice-flour pasta is virtually indistinguishable from a gluten one: or, you could make your own pasta with fresh eggs and gf flours. And there you have it, "fake" mac and cheese, low in histamine.
Obviously, that's a pretty simple example. Start out that way, and the more experience you have with experimenting in the kitchen, the more complex substitutions you'll be able to make.