ItemsAdder allows to add custom furnace recipes for your items, to turn them into something else.
Note: Smelting permissions cannot be reliably enforced, since it is not possible to precisely determine which player placed the item.
For example, if a machine pulls items from inventories, there is no way to track which player originally inserted the item into the first hopper.
If you need to enforce permission you should implement it in a crafting recipe.
Example
When adding a cooking recipe, will you need to add the cooking section under recipes. The name shouldn't matter that much, but it is recommended to use the one of the result.
In this example I created a cooking recipe called cooked_sausage.
item is the item that should be cooked. Both Vanilla Minecraft and custom items can be used through their respective namespaces.
machines is a list of allowed furnace types that can smelt/cook the item. Supported are FURNACE, BLAST_FURNACE and SMOKER
exp defines the amount of experience the player gets when taking out the item.
cook_time is the time it should take for the item to be processed. The time is in ticks, which means that 20 = 1 second.
result contains the item and amount option, which define what item and how much of it should be returned. Both Vanilla Minecraft and custom items can be used through their respective namespaces.