Combine all of the seasoning ingredients in a small bowl and set aside.
In a medium pot with a lid, heat the oil over medium until shimmering. Add the popcorn kernels and cover. Shake the pot once in a while to stir the kernels. Once popping starts, stay near the pot and listen. When popping slows to 1 or 2 seconds between pops, remove the pot from the heat and dump the popcorn into a bowl, to prevent burning. Drizzle the butter over the popcorn (if using) and then liberally sprinkle the seasoning over the popcorn, tossing lightly between sprinkles.
Notes
Vegan option: Equally delicious dairy-free! Here's what you do: For the spice blend, replace the parmigiano with the same amount of nutritional yeast. Also, replace with the butter with a quality buttery spread, such Miyoko's Eurpean Style Cultured Vegan Butter. Delish!