Slice the pork loin into small strips (slightly freezing the pork helps, but this doesn't have to be exact). For the pork marinade, combine the gochujang, soy sauce, garlic, ginger, honey, and apple cider vinegar and stir to combine. Set aside 1/3 of mixture for future use. Add remaining marinade to blender along with one apple. Blend to combine and add to large plastic bag along with pork. Marinade for 2-4 hours.
Once pork has been marinaded, begin preparing the toppings and rice. Preheat oven to 450 degrees. Place small sided dutch oven or cast iron pan* into the oven.
As dutch oven heats. dice red pepper/remaining apple/scallions and slice cabbage; set aside. In skillet or medium saute pan, saute mushrooms in a bit of oil for 5-7 minutes or until brown. Season with a few dashes of soy sauce. Remove mushrooms, and in same pan, wilt spinach for 2-3 minutes.
Place saute pan over high heat. Sear and cook the pork in batches, ~5 minutes a batch depending on size of cuts. Be sure not to crowd the pan!
Once pork is cooked and resting, remove dutch oven from the oven. Add in enough saute oil to coat the bottom, and add in rice, topping with the reserved marinade. Rice will crackle and pop; thats okay! Place back into over for 5 minutes, stirring halfway. Once rice is cooked, remove from oven, cover with pork and toppings and serve immediately!