Sauté the pepperoni. Place a large pot, big enough to pop popcorn in, on the stovetop. Add in the pepperoni and turn the heat to medium-high. Cook until the peperoni begins to crisp and the fat renders out. Using a slotted spoon, remove the peperoni but leave the fat in the pan. If you don’t have enough oil to coat the bottom of the pan, add a little canola oil to supplement.
Pop the popcorn. Heat the oil until it’s really hot. Add the popcorn kernels and pop over high heat, shaking pretty consistently until popcorn is popped. Once popped, add the Italian seasoning, pepperoni, parmesan cheese and toss to coat.