Reduce the wine by half with the thyme. Turn the heat down while slowly whisking in the cheese so that it emulsifies into the wine, getting thicker as you go. Season with salt and pepper.
Transfer into a suitable serving pot.
Cut the bread and use to dip into the fondue.
«Gorgonzola is really the star of the show here, the gruyere is just used to make the mix go slightly more stringy.»