Place the kernels in a brown paper bag. Fold the top of the bag over three times.
Place the bag in the microwave standing upright. Microwave on medium power for 2.5-3 minutes, until the popping slows to a pop every 3 seconds.
Open the bag (see Note) and add the butter and salt. Refold the top of the bag and shake the bag to coat the popcorn. Eat immediately.
Notes
Want to change it up? Top your popcorn with white cheddar powder, taco seasoning, everything bagel seasoning, or drizzle on chocolate. The sky is the limit as to what you can top popcorn with!