itch.io

You need to choose the ingredients for the meal first, for example if you want to cook Soup you need to tap Seasoning, Vegetable, and Piece of Meat then click "Combine All" after that the recipe for Soup will be added, if you play on Android you can simply hold the recipe to cook it(of course if you have the ingredients)

The same with other recipe such as Omelete and other

You don't necessarily need the recipe book, as long as you memorize the recipe you can add it your own, please note that if your character already learn the repice for that spesific food you don't need to put the recipe again.