The Healthy Stew item added by the mod has a unique dynamic recipe. The recipes for it are created on world load/reload. The ingredients for the recipe are provided via the #genesis:healthy_stew_contents item tag. The recipe will always consist of two distinct items found in this item tag, along with a bowl.

To add a potential ingredient to the recipe of the Healthy Stew item, add the item to the #genesis:healthy_stew_contents item tag. Alternatively, if you want to remove an item from the recipe or remove all recipes, you can do something like this:

{
  "replace": true, // To remove an item or multiple items, this must be true.
  "values": [
        // Leave empty for no recipes.
  ]
}