Ingredients:
First heat some oil, then fry the onions and garlic till the garlic is slightly brown. Then, add in a bit of dark soy sauce and water and fry some more.
Aadd more water till the onions and garlic are totally submerged, and let it cook for like 10 minutes or so, to let the flavours come out. Let the water boil away while waiting.
Add in the potatoes and the beef, then add oyster sauce and ketchup. If necessary add a bit of water so the majority of the ingredients are submerged in liquid. Cook under a low fire for at least 30 minutes, making sure you stir it from time to time. also taste and add more oyster sauce or ketchup if you think it needs more flavour. Add sugar at this time if you want it to be more sweet. You can leave it simmering for like 2-3 hours to get softer beef.
If you want to add spices for a more complex taste, add one star anise and 1-2 cloves in when frying the garlic and onions. You can also add in the beef at this time to fry it slightly for a different texture.