Cut Pork Belly (2 pound) into 8 thick pieces, season with Kosher Salt (to taste) and Freshly Ground Black Pepper (to taste).
Saute pork belly on all sides until golden brown.
Remove pork from pan and reserve.
In the same pan, saute Carrot (1/2 cup) and Onion (1/2 cup) until caramelized. Deglaze with Red Wine (3 cup).
Return the pork to the pan and add Beef Stock (3 cup).
Cover pan and simmer until pork is tender, about 2 1/2 hours.
Meanwhile, cook Potato (2 pound) in salted water and drain.
While the pork and the potatoes are cooking, saute Onion (1 cup) in Butter (6 tablespoon) and Olive Oil (3 fluid ounce) until translucent.
Add Napa Cabbage (1 head) and Chicken Stock (1 cup). Saute until cabbage wilts.
Add the cooked potatoes.
Mash the potatoes coarsely. Season with Kosher Salt (to taste) and Cayenne Pepper (to taste).
If the potatoes are too dry, add olive oil until the puree has the desired texture.
When the pork belly is tender, add Scallion (1/2 cup). Check and adjust seasoning.
Plate the potato puree. Top with the pork belly and sauce, or serve pork belly and sauce separately.