It's tremendously successful, and he says this:
Now we can afford real bowls of pretzels instead of trompe l'oeiling them on the bar.This is a fantastic bit of morphology. It's yer bog-standard noun-to-verb conversion (verbification, if you like), transforming the noun trompe l'oeil to a verb to trompe l'oeil (and notice, of course, that the noun is itself a translation of a French verb-plus-object: 'to fool the eye'). Then we are free to stick the verb suffix -ing on the end, because we can do that with verbs in English.
But it's so cool. For one thing, it means that the normally unpronounced final 'l' gets pronounced (he says it like trompe-loyling) and for another, it reveals how when we borrow a phrase wholesale with an idiomatic meaning like this we can put a verb suffix on a noun no problem at all.