Importing the class

Link to importing-the-class

It might be required for you to import the package if you encounter any issues (like casting an Array), so better be safe than sorry and add the import at the very top of the file.

import crafttweaker.api.recipe.type.SmokingRecipe;

Extending AbstractCookingRecipe

Link to extending-abstractcookingrecipe

SmokingRecipe extends AbstractCookingRecipe. That means all methods available in AbstractCookingRecipe are also available in SmokingRecipe