Nice! I never tried that on grilled cheese! ... but I have a jar of Aromat in the kitchen, too...it's similar to Maggi's "Fondor," which Germans use in their salads (salat) and vegetables (gemuse) and french fries (pommes).
On french fries (or belgium thick ones too) Aromat is the best! I skip the salt and use Aromat whenever I eat fries.
Hmmm. Salad with Aromat, that is a good one, have to try that.
OK, now going out of this screen, it is making me so hungry.