Blend together all sauce ingredients. Set aside.
Soak short ribs in a bowl of cold water for 30 minutes. Dump out water, rinse ribs to get rid of bone fragments.
Add ribs to an oven safe, deep sauté pan (or pot) and add enough water to cover them. Add in whites of green onion, half onion, peeled radish, garlic and black peppercorns. Turn on heat to medium high. Bring to a boil and allow to boil for 10 minutes, skimming foam off the surface.
After 10 minutes, remove broth from heat and take out ribs. Strain broth and set aside.
Add ribs back into clean pot and pour blended sauce over them. Mix to coat the ribs, then add about 3 cups of water (just so they are barely visible on the surface.) Bring to a boil and cook for about 30 minutes. Reserve leftover broth.
Add potatoes and carrots to pot, mix so they are coated in sauce and submerged in the sauce. If your sauce starts to get too dry, add more broth 1/4 cup at a time. Allow to boil for 20 more minutes, stirring occasionally, until potatoes are tender.
Add rice cakes and cook until they are soft, about 1-2 minutes. Remove from heat.
Top ribs with mozzarella cheese and torch with blowtorch, or place in over to broil for 2 minutes until cheese melts. Serve with a hot bowl of rice.