GregTech recipe support use a Reflection API.
List all recipe variable you can find here
Use
Code
MTUtilsGT.addCustomRecipe(String recipeVar, boolean aOptimize, long aEUt, long aDuration, long[] aChances, IItemStack[] aInputs, ILiquidStack aFluidInput, ILiquidStack aFluidOutput, IItemStack[] aOutputs);
or
for add or remove recipe.
Ex.
Code
import mods.MTUtilsGT;
MTUtilsGT.addCustomRecipe("sShredderRecipes",true, 128, 128, [10000],
[<minecraft:stone>], null, null, [<minecraft:diamond_block>]);
Add this recipe