Put the popcorn kernels in the brown paper bag and roll the top over 3-4 times. Microwave on high for 1-2 minutes (my microwave is dinky and is much less powerful than my parents', so I'd start with 1 minute if you're unsure).

Scoop the popped popcorn out of the bag into a large bowl, leaving the un-popped kernels. Microwave for another minute, or until the pops slow down. Add to the bowl of popped popcorn.

Melt the butter.

Mix together the sugar, cinnamon, and salt.

Slowly pour the butter over the popcorn, tossing with your hands about halfway through.

Sprinkle the cinnamon sugar mixture over the top of the popcorn and toss well to coat. Dig in.