01In a large (8- to 10-quart) stock pot over medium heat, pour 2 tablespoons of oil. Add 2 kernels and cover. Once those the kernels pop, add 1/2 cup of the kernels. Cover and cook, shaking the pot every 20 seconds, until all the kernels pop, about 2 1/2 to 3 minutes, shaking the pot every 20 seconds. Remove from the heat and pour the popcorn into a large serving bowl. Return the pot to the stove and repeat the process with the remaining 2 tablespoons oil and 1/2 cup kernels.
02While the second batch of kernels pop, place a small pot over medium heat. Add the butter and 2 teaspoons rosemary. Heat until butter is melted, stirring a few times. Remove from heat and set aside.
03In a small bowl, gently toss the cheese and the remaining 2 teaspoons of rosemary together.
04Once all the popcorn is popped and in the serving bowl, gently add the rosemary cheese mixture, tossing lightly with your hands or a spatula. Add the salt and black pepper (if using), and gently mix again. Slowly pour the melted rosemary butter over the popcorn. Carefully mix until all the kernels are buttered. Serve immediately.