Preheat the oven to 350 degrees F. Heat the sesame oil in a braising pan over medium-high heat until smoking. Season the pork with blackening spice, then sear it, skin-side down. When the skin begins to crackle, flip the pork and add the leeks, garlic and ginger, and cook until the leek begins to wilt. Add the vinegar, soy sauce and sugar and stir to dissolve the sugar. Cover and bake until the meat is tender, 2 1/2 to 3 hours. Remove the meat from the braising pan and let cool. Slice into 1/2-inch slices.
For the miso broth:
Poach the bacon in 1 quart water for 30 minutes. Meanwhile, soak the kombu in 2 quarts of water. Combine the two liquids, then using a fine-mesh cone strainer, steep the miso paste and bonito flakes into the broth. Simmer very slowly for 1 hour, still with the strainer set into it (do not boil or the broth will become murky). Remove the strainer and the kombu from the broth and keep the broth warm.
For the ramen:
Bring a large pot of water to a boil and add the noodles. Cook about 7 minutes, then strain and place in a wide serving bowl.
Add enough miso broth to the bowl to cover the noodles. Dress with 3 slices pork rib, the sprouts, pickled egg and scallions.