Script:
import mods.gregtech.BlastFurnace;
BlastFurnace.addRecipe([<gregtech:gt.metaitem.01:2819>, null], <gregtech:gt.metaitem.01:2865>, <gregtech:gt.metaitem.01:2020>, 500, 480, 2000);
gregtech_1.7.10-5.08.29
GTTweaker-1.7.10-1.0.1
Same GT + GTTweaker-1.7.10-0.7.6 + double recipe adding string in script + reentering world = it works.
You dont need the null
BlastFurnace.addRecipe([<gregtech:gt.metaitem.01:2819>], <gregtech:gt.metaitem.01:2865>, <gregtech:gt.metaitem.01:2020>, 500, 480, 2000);
would be ok too.
GT Tweaker 1.0.1 is for Minetweaker 3.0.10
GT Tweaker 0.7.6 is for Minetweaker 3.0.9C
I test your recipes with my settings.