Stir the popcorn kernels and 1/2 cup of the Rosemary-Infused Oil in a large, heavy pot over medium heat. Cover and cook, shaking the pot halfway through cooking, until the kernels have popped, 8 to 9 minutes.
Immediately transfer the popcorn to a large bowl. Add the Parmesan, salt and remaining 2 tablespoons Rosemary-Infused Oil; toss to coat.
Combine the oil and rosemary sprigs in a small, heavy saucepan over medium heat. Cook until fragrant, about 5 minutes. Let cool to room temperature.
Place the rosemary sprigs in a 16-ounce bottle or cruet. Add the oil and seal the lid. Use immediately or refrigerate for up to 1 month.