Add 3.4 fl oz (100ml) of the coconut milk with water to a pot set over low heat. Place your beef chunks into the pot and allow them to simmer slowly for 2–3 hours. The beef should be fork-tender upon completion, but keep in mind that thicker cuts may require more time. If you own a pressure cooker, this is the perfect opportunity to use it and cut down on the cooking time.
Once your beef is tender, remove it from the pot along with 10.15 fl oz (300ml) of the liquid it was braised in. Transfer both the meat and the liquid into a bowl and set aside.
Pour 6.8 fl oz (200ml) of coconut milk into a wok and heat it over low-medium. Simmer the milk until you notice the coconut oil beginning to separate from the milk.
Add the massaman curry paste to the wok. Stir and cook until oil starts appearing on the surface.
Now, pour in the remaining coconut milk along with the reserved braised beef and liquid. Add the carrots, onions, potatoes, cinnamon stick, star anise, palm sugar, salt, tamarind paste, and fish sauce. Continue to simmer the curry until the potatoes and other vegetables reach your desired softness.
Stir in the roasted peanuts and then remove the pot from the heat. Serve immediately with steamed rice. Enjoy!