You can add recipes with CraftTweaker. Just add zs files to script directory.

This mod adds some methods, WorkbenchPlus.addRecipe(IIngredient[] input, IItemStack output, float energy), WorkbenchPlus.removeRecipe(IItemStack output), WorkbenchPlus.removeRecipe(String id). removeRecipe(IItemStack) removes all recipes for the parameter item. removeRecipe(String) removes recipe with the parameter id.

This is an example.

import mods.quarryplus.WorkbenchPlus;

WorkbenchPlus.addRecipe([<minecraft:iron_ingot>*2, <minecraft:gold_ingot>, <ore:plankWood>*3], <minecraft:iron_leggings>, 600.0);
WorkbenchPlus.removeRecipe(<quarryplus:quarryplus>);
WorkbenchPlus.addRecipe([<minecraft:diamond>*2, <minecraft:gold_ingot>, <ore:plankWood>*3], <quarryplus:quarryplus>, 5151.0);
WorkbenchPlus.removeRecipe("quarryplus:builtin_pumpplus");

This script file adds 2 new recipes, iron_leggings and quarryplus. Also it removes all recipes for QuarryPlus and a recipe whose id is "quarryplus:builtin_pumpplus". IDs of built-in recipes is written in json files in config/quarryplus/defaultrecipes.

See this page and this example.