what makes your think it was another restaurant? here is a quote from this article (https://www.metroweekly.com/2015/04/from-scratch-james-alefantis/amp/) from an interview with Alefantis regarding Comet:

MW: What was it they couldn’t believe you had made?

ALEFANTIS: Well, we make everything from scratch. Other restaurants, even good restaurants, will, like, not roast their own peppers. You can just buy the roasted peppers in a can. Or you can buy garlic oil. Some products you can get, and they’re consistent and they’re easy. But I didn’t even know that existed actually until they said that. I was like, “What do you mean? There’s another way? You can just buy these things?” Because a lot of restaurants will open a can and put it on. Like our sauce — we harvest a whole crop of organic tomatoes — 10 tons of tomatoes every year. Can them all, store them in the basement, have like a harvest party when it gets loaded in.