Keep the heat fairly high. Add the sugar to the empty pan and swirl it around a few times to coat it with the pork’s cooking juices. Then push it to the center of the pan and let it melt.
You’ll see—the sugar should melt and spread across the pan.
Add the soy sauce and nuoc mâm sauce to the hot caramel. Be careful of caramel splatters—they could burn you. As soon as you’ve added the sauces, turn off the heat and mix well with the caramel using a wooden spatula.
Add the meat and simmer for 10 minutes over low heat, covered.
Notes
If you want a dish with a richer, creamier sauce, you can add half a liter of chicken broth and a teaspoon of cornstarch at the same time you add the nuoc-mâm and soy sauce. Let it simmer over low heat, uncovered.