Movie-Theater-Style Popcorn

Combine all ingredients in a medium heavy pot (preferably cast iron). Heat over high, stirring, until butter melts. Cover, reduce heat to medium-high, and cook, undisturbed, until kernels begin popping rapidly.

Offset lid to create a 1/8-inch vent along one side of pot; continue cooking until popping begins to subside, about 2 minutes. Transfer popcorn to a large bowl; toss until cooled slightly, about 2 minutes. Serve.