Deweirding

After the material and conceptual worlds merged together after The Curtain fell, most of the edible plants growing in the wild became "weird", gaining many unusual properties, some of which manifest after they get eaten. Similarly, eating the meat of spirits can also bring many unexpected effects. And since not everyone wants something weird happening to them whenever they decide to eat, people have been looking for ways to deweird them and turn them back into normal food.  

Methods

Psychological

One of the methods, simple in theory, hard in execution, is to treat and consider any weird ingredients as their normal counterparts. When treated like that for the whole preparation by someone skilled enough in this, the ingredients will start to lose any of their unusual properties. Particularly skilled chefs may be capable of removing any undesired traits while leaving something like their unusual taste or texture.  

Normalization through exposure

This method requires large amounts of normal produce. Then, the spiritually-modified one needs to be placed among them. It is important that the normal ingredients have to heavily outbalance the amount of the unusual ones. If done right, the "weird" ingredient will start to lose any property that makes it unusual. Some modified produce can be resistant to this method and might infect the normal produce instead.  

Spiritual

There are some spirits that can change the weird plants into their normal counterparts, mostly spirits of nature, crops, production, and some animal spirits. Deals like that tend to come with costs, though, so one should watch out and be ready for that.  

Ritualistic

There are multiple rituals that can either infuse or suck out spiritual energy from most things. Performing them might require costly reagents, knowing specific spells and actions, or even require precise conditions to be met. And even then, they might fail should the "caster" not have a certain aptitude for the rituals needed in purification.