This page relates to Create, which does not have built-in support, you will need to install CreateTweaker as well!
Link to create-splashing
The Splashing mechanic is a type of IRecipeManager and implements all the methods that are available to IRecipeManager's, such as
Link to methods
Link to add-recipe
The following script will add a recipe that will output a Diamond and an Apple 45% of the time when a piece of Dirt is Splashed with a duration of 100.
// <recipetype:create:splashing>.addRecipe(String name, MCWeightedItemStack output, IIngredient input, @Optional(100) int duration) <recipetype:create:splashing>.addRecipe("splashing_test", [<item:minecraft:diamond>, <item:minecraft:apple> % 45], <item:minecraft:dirt>);
Link to remove-recipes
The following script will remove all Splashing recipes that output Yellow Concrete.
// <recipetype:create:splashing>.removeRecipe(IItemStack output) <recipetype:create:splashing>.removeRecipe(<item:minecraft:yellow_concrete>);