Heat the Oil:
In a large, heavy-bottomed pot with a lid, heat oil over medium-high heat. Add 2–3 popcorn kernels and cover. When they pop, the oil is ready.
Add Kernels:
Add the remaining popcorn kernels to the pot in an even layer. Cover and remove from heat for 30 seconds (this helps all kernels reach a similar temperature and pop evenly).
Pop the Corn:
Return the pot to heat. Once popping starts, gently shake the pot occasionally to prevent burning. Continue until popping slows to 2–3 seconds between pops. Remove from heat immediately.
Season:
Pour melted butter over the popcorn if desired and sprinkle with salt. Toss to coat evenly. Add any additional seasonings or toppings as desired.
Serve:
Transfer to a large bowl and enjoy warm.