1 teaspoon oil, or to taste
1/2 cup popcorn
1/2 cup fat-free Parmesan cheese, or to taste
1/4 tablespoon salt (optional)
Have Parmesan cheese and salt mixed in a measuring cup and ready by the popper. Have a bowl ready for popcorn.
Put oil and popcorn into popper. Fasten the lid securely and stir constantly over high heat. Popping should start in about 2 minutes. Remove from heat when popping almost stops.
Quickly open lid and pour mixture over hot corn then close lid and continue stirring (no heat) until thoroughly mixed. Pour into large bowl.