A few years ago, I was dead set on the idea of making homemade panna cotta. The Italian dessert requires gelatin, and to make the Wife happy, I agreed to make it with vegetarian gelatin. (When you think of it, the fact that there's a little bit of animal intestine inside many fancy desserts is a bit queasy-making.)
Soon enough, I discovered that non-animal gelatin was nearly unobtainable. No one carried it. No one had heard of it. After much searching, I was finally directed to the curiously named New York Cakes and Baking Supply on W. 22nd Street near Sixth. (Why "Cakes" and "Baking"? Why not just "Baking"? The pairing of a noun and verb in the name is very unsettling, somehow.) Upon stepping inside, I knew I had found the locus of all serious bakers in NYC. They had everything, including things that have probably never occurred to you. Every sort of cake mold. Everything you could think to put in or on a cake, and a few dozen items that would never have occurred to you. Fillings, decorations, utensils, various types of chocolate, cookie cutters, colorings, extracts, pastes, etc.
I found my vegetarian gelatin, but was warned it would not work as well as animal gelatin. (They were right.) When, a while later, I needed unbleached parchment paper for a certain fish recipe, I knew where to go. I haven't seen another store like it. I imagine that, if it ever sent out of business, certain items would suddenly become unavailable in Gotham, and the quality of cakes and such would plummet in the City.