Heat the butters in a small skillet over medium heat. Once they start to shimmer, stir in the oregano, dill, thyme and crushed red pepper flakes, then turn off the heat so the herbs and pepper can infuse the oil. Let sit for 10-15 minutes.

While the butter infuses, pop the popcorn kernels in an air popper, covered skillet, or using your favorite method. Transfer it to a large paper bag. While the popped kernels are still warm, drizzle the butter mixture over, then close the bag and shake to coat the popcorn. Sprinkle on the cheese and season with salt, close the bag, and shake again to combine. Add more salt and/or red pepper flakes to taste, and serve!