How can I make butter popcorn with my kettle popper?

At the movie theater, they pop the corn in butter flavored oil, and then pour more artificial 'butter' on it when it's served. To use real butter at home, try this: Pop corn as usual in your popper. Dump the popped corn into a large paper bag, pour in melted butter, sprinkle with salt, if desired. Fold top of bag over, and shake well. This distributes the butter all over the popcorn.