I had the earlier version, from the mid-60s, called a Vac-u-form. Didn't make edible stuff, only plastic toys from molds and plastic sheets. You'd put the form down on the plate, then clamp the plastic sheet into place over it. The plastic sheet was heated and, when it got soft, you pumped like hell on a lever on the side of the machine that evacuated the air under the plastic. The plastic then shrank down over the mold to make a plastic toy. And yes, potentially dangerous -- today's kids wouldn't be let near it. I think I burned myself a time or two, but nothing serious.
Here's a link. I had the first version shown on that page. I can still smell the stink of that hot plastic -- pleasant memory, though.
http://www.samstoybox.com/toys/Vac-U-Form.html