Not only did I find a place that makes it fresh and serves it to you in a cone, but they have pints for you to take home too!!! It's pricey (like about $5 after tax) but SO incredibly worth it. Cones are cheaper, but I don't remember how much.
I discovered Black Sesame Ice Cream at
Cafe Zaiya. It's less than 1/2 a block away from the 42nd St Library. Literally, if you walk out of the library, down the steps, between the lions and straight across the street to the next block, it will be on your right side.
It's a perfect treat after accomplishing some writing goals in the Rose Reading room. And it's even better than the stuff in Kyoto.
And if you're really hungry, I have to admit that Chiyoda sushi next door to Cafe Zaiya is not bad either. They actually had my favorite sushi (that I have not been able to find in the U.S.) negi-toro which is fatty tuna with Japanese green onion.