Pre-heat oven to 350 degrees F (176 C).
Add all ingredients (except for the low-moisture mozzarella and green onion) into a large bowl. Mix thoroughly. If your cream cheese isn't very soft, it might be better to mix everything with your clean hands.
Once everything is all mixed up and there are no big hunks of cream cheese left, add the mixture to a 1 to 1.5 quart-sized, shallow baking dish.
Sprinkle the low-moisture mozzarella cubes on top of the baking dish and add it to the oven. Bake in the oven, uncovered for 30 minutes.
Remove baking dish from the oven and stir everything together to incorporate all the melty cheese.
Top with green onion and serve with tortilla chips, pita bread, crusty bread or even soft pretzels.
Notes:
You can buy gochugaru (course pepper flakes) online (Amazon affiliate link).
You can also buy gochujang online (Amazon affiliate link).
If you want to know more about cheese buldak or cheesy fire chicken, I turned it into a sandwich and wrote about it.