Use a sharp kitchen knife to cut the pork
fats into thin strips and make deep cuts in the beef. Ensure that the
cuts are evenly cut on the beef. Push and insert a sliver of pork fat
into each of the cut. Use a large pan to place the beef. The pan should
has a tight-fitting lid. Add onion, vinegar, tomato, soy sauce and bay
leaves. Bring the liquid to the boil, then reduce to gently heat and
simmer with a lid. Cood for 2 hours until the beef is tender. Season
with salt and black pepper. Continue to simmer without a lid for another
30 minutes. Add the potato and sweet potato. Continue to simmer,
uncovered until tender.
Remove the beef from the pan and cut into
thin slices. Drizzle over the gravy and serve with the potato. Scatter
some chopped cilantro leaves over the top as garnishing.