UPDATE 3/28/13: I have been using a foil lid for the pan instead of the pan lid, and it works much better. Prepare a piece of foil with holes pricked with a fork before heating pan of oil. Once popcorn kernels have been added to the pan, quickly secure the foil over the pan as a lid. This method yields more popped kernels for some reason.
1 Tbsp. canola oil or ghee
1-2 Tbsp. unsalted butter, melted
fine sea salt, to taste
Get out a large bowl and place it near the stove. Heat canola oil in a large pot. Add one kernel and wait for it to pop. Once it does, carefully remove it from the pot. Add enough popcorn to cover the bottom of the pot in a single layer. Quickly cover it with a lid. Using a potholder, carefully hold the lid on the pot and shake it every 10 seconds or so. Keep shaking until the popping stops or almost stops. Remove from heat and pour into large bowl. Pour on melted butter and salt, and mix to combine.