At home, lechon kawali often goes with ketchup if lechon sauce (the kind with liver base) is not available.
In carinderias, a dipping sauce made with vinegar, soy sauce, sugar, chopped raw onions, garlic, ginger and chilies is served on the side.
The trouble with ketchup is that it drowns out the natural flavors of the meat. Lechon sauce takes some effort to make unless one is willing to compromise with the bottled kind which looks and tastes suspiciously bereft of liver and thickened primarily with bread crumbs and nothing more.
The carinderia dipping sauce, I often find so strong that it leaves a dry sensation in my mouth (too much acid does that).
So, I went about experimenting with something that I really, really like. No compromises.
Start with a mixture of two parts balsamic vinegar and one part patis. Add meat broth, little by little, tasting as you go. When the mixture tastes right (i.e., it’s no longer so strong that it overwhelms the taste buds and palate), add enough sugar to balance the acidity of the balsamic vinegar. Then, toss in some finely sliced onion (shallots are better, if you have some), smashed whole garlic cloves, slices of ginger and lightly pounded bird’s eye chilies. Let sit for at least half an hour to allow the flavors to blend together.
Is this dipping sauce served on the side? You can do that. I prefer spooning it over my lechon kawali just before serving.