Cool question. I‘d imagine the easiest way I can at least think of is spraying it with liquid nitrogen. The challenge will be to get the nitrogen back in the bottle and keep it liquid in the meantime.
Properly flash-frozen ice cream is actually very smooth since the ice crystals are very small. The water freezes before it has a chance to form large crystals.
Haha probably, but it was the only thing I could think of that people would want to be cold faster. Maybe some other desserts, like lemon meringue or banana cream pies.
I‘m baffled our usernames only differ by one letter. My idea was, if you „sprayed“ the item from afar, it would cool the surrounding air and only ever so slightly touch that item. I don’t think this would flash freeze it. Feel free to correct me.