Prepare the ingredients: Peel and rinse the potatoes in water and cut them into one inch cubes. Roughly chop the onion and set them aside. Rinse the beef in running water and cut them into smaller half an inch cubes, which will help to tenderize the meat and also make them into bite size pieces.
Sear the beef: Preheat a pot on medium low heat. Drizzle the cooking oil and add the beef cubes in the pot, and then cook for two minutes while stirring, or until golden brown.
Fry the onion and paste: Remove the beef cubes once it’s browned. Then, add the onion and cook for three minutes while stirring. Thereafter, add a tablespoon of cooking oil and add the massaman curry paste. Press down on the paste and stir to fry the paste for one minute. The paste will fry very quickly and release a deep, rich and aromatic fragrance. Add the coconut milk, cinnamon stick, cardamom pods, bay leaves and potatoes, and stir to mix everything for one minute.
Add the remaining ingredients: Back goes in the beef cubes, then add fish sauce, brown sugar, fresh lime juice and one cup of water. Simmer for fifty minutes with the lid closed and continue to add one cup of water every ten minutes. Generously sprinkle the roasted peanuts all over the curry, add fresh basil and serve with fluffy rice.