Pop the popcorn using a large, heavy pot with a tight-fitting lid or a popcorn maker.
Coat the bottom of the pot with vegetable oil and heat over low heat. Drop in 1 kernel of corn and when it pops add the remaining corn, cover and shake pan. Continue to shake pan until all the corn has popped, being careful not to burn.
Place the popped popcorn in a large bowl. Drizzle with the melted butter and sprinkle with the cheeses. Toss gently to combine and serve immediately.
Recipe courtesy of Giada De Laurentiis