Heat the oil and 2 of the popcorn kernels in a large, heavy-bottomed pot or saucepan with a lid over medium heat until the kernels pop, about 3 minutes.  

Remove the pot from the heat and discard the two pieces of popped popcorn.  Pour the remaining popcorn kernels into the pan ans give it a shake to coat the kernels in the hot oil.  Cover the pot and let it sit for 60 seconds off the heat while the kernels warm up without burning the oil.  

Place the pot back over medium heat, and cook the popcorn, giving the pot an occasional shimmy to cook the kernels evenly and ensure there are no hot spots. Once the kernels start to pop, tilt the lid slightly to let steam escape.

Continue to cook the popcorn over medium heat until the popping sounds slow down to one pop every 2-3 seconds.  If the popcorn starts to overflow the pot, just tip some of it into a bowl and keep cooking until the popping slows.

Remove the lid and dump the popcorn into a large serving bowl.  Sprinkle with a salt, to taste, or drizzle with 2 tablespoons of additional olive oil or melted butter first and other popcorn seasonings, if desired.  Toss the popcorn to distribute salt and other seasonings evenly, then serve popcorn immediately.