Before cutting the pork belly into cubes, scrape the surface of the skin with the edge of a knife with rapid strokes to remove gunk. After cubing the pork, parboil in a 4-5 L pot for about 10 minutes. Then, pour out all of the scum that has risen to the surface as well as the meat. Thoroughly rinse out the pot and each morsel of meat. Return the meat to the pot, spacing each morsel evenly along the bottom of the pot. Pour in the coconut juice and simmer over medium high heat, occasionally turning the meat to ensure that all sides are cooked in the juice.
While the pork belly simmers in the coconut juice, combine in a small bowl the diced onions, minced garlic, fish sauce, sugar and ground pepper. Give the mixture a stir and set aside.
Once the coconut juice has completely reduced and started to caramelize, drizzle the nước màu over the meat. Then add the fish sauce mix and enough hot water to cover the pork belly by 2 cm (about 1.25 L). A word of warning for the uninitiated, the fish sauce mix will give off a strong odor the minute it is added to the pot, so you might want to turn the range hood to maximum. Cover and simmer over medium-low heat for about an hour.
Remove the lid and turn the heat up to medium-high. Peel the hard-boiled eggs from their shell and add to the pot. Simmer for another 15-20 minutes to allow some of the liquid to reduce, leaving enough liquid to cover half of the pork belly. The liquid can be further reduced if you prefer a more concentrated sauce. The eggs will likely only be half-submerged, so turn each of them after about 7-8 minutes to ensure that they are uniformly colored by the liquid.