they take up to 20 kids at one time because it's all the space they have. I've seen them take kids older than 10 and kids younger than 3. There really isn't age limit but it is really geared for the younger set. Older kids might just get bored. There are 2 CMs who run the show.
What they do is give each kid their own personalized chef's hat, line up the kids on the podium, then proceed to explain what goes into making a Nestle toll house chocolate chip cookie. Each child is given a chance to put in an ingredient or stir the dough. Then each child gets to dump 2 cookie doughs on the sheet. This then goes in the oven and then when it's done, each child will get 2 cookies to take away. They used to give the container of chocolate chips, but they don't do that anymore. The kids just get the cookies and their chef's hat.
They run each hour from 12:30pm-4:30pm. If it's crowded, you may want to get there early and line up. The show lasts 20-30 minutes, so do plan to set aside that time. You'll want to have the camera handy too, because it's really cute.