The one I loved was a pancake machine at a hotel breakfast buffet. You pressed the pancake button and batter was dispensed onto a slowly rolling large heated cylinder. When your pancake made it to the edge of the cylinder, it peeled off and flipped onto another counter-rotating cylinder. Then it was peeled off and slid down a chute onto a plate. Perfectly round, perfectly cooked.

I ate a few more pancakes than I should have just to see it work. Then against the protests of my wife I lifted the hinged side panel to see how the batter was loaded and dispensed (it was squeezed out of a bag by a screw jack)

The girl at the buffet asked if I was a process engineer (yup) and assured me that I was far from the first to peek under the hood 😅