Cut, pour, take off heat when popping stops.
Here's a heads up (do take notes): That doesn't work with an electric kettle.
What you get is a device that automatically shuts off the moment things start getting a bit hot, leaving you with roughly 6 popcorns and about 60 unpopped kernels. What's more, you can't even reheat until the kettle has cooled down, which takes about 10 minutes.
Electric kettles: thwarting attempts at eating healthy. *
* Popcorn is healthy, right?