On this page of the guide to Genshin Impact you will find out how to cook different dishes, where to get recipes and what bonuses do eating prepared meals offer.
In Genshin Impact you can create different dishes from ingredients, these dishes give you different bonuses. The most common benefit is immediate recovery of a portion of your life points. But there are dishes that reinforce some of your team's stats. Some dishes can even resurrect a fallen hero. You can get the ingredients from shopkeepers or by picking them from different trees or shrubs. In contrast, recipes can be bought from vendors or acquired while performing tasks. To unlock a dish, you need to find the recipe in your equipment and read it.
The dishes are prepared at a campfire - to create one, press the button at the right moment (during cooking animation) If you complete the action correctly, you'll get Proficiency (if it's at a maximum, you'll be cooking automatically). At a campfire, you can also turn a particular ingredient into a different one, e.g. meat into sausages. This procedure takes time - you need to wait a little bit before getting the ingredient. It's worth remembering, however, that you don't have to pick up an ingredient from the same campfire! You can pick up an ingredient from a completely different fire. It is also worth noting that some fires can get extinguished - in such cases, you need a character that has the Pyro element to light them again. All you need to do is use your Pyro skills close to a campfire and you'll light it. You also need to know that characters can't always treat themselves with food, because after eating a few such dishes, the character will be full and won't want to eat anything. (If you feed all the characters in the Party to such a level that they don't want to eat anything anymore, you get a hidden achievement (Bon Appétit) giving you 10 Primogems).