Marinate the chicken pieces in 1 tsp vegetable oil and 3 tbsp massaman curry paste. Let it sit in the marinade for at least 30 minutes.
Peel the potatoes and cut them into large quarters.
In a heavy bottomed sauce pan or a wok, take the rest of the vegetable oil and heat it.
When the oil is hot, add cardamom, cinnamon and star anise. Let the spices release some fragrance. Then add the shallots and fry on medium flame.
When the shallots are golden brown, add the potatoes and fry them on medium heat for 2 - 3 minutes.
Then add the marinated chicken and stir fry on high heat so that the chicken gets some colour.
After 4 - 5 minutes, add coconut milk (leaving aside 1/4 cup), fish sauce and just about enough warm water to cover the chicken pieces.
At this point, if you feel the need, then add another tbsp of massaman curry paste.
Let it boil for a couple of minutes and then cover and cook on low heat till the potatoes and chicken have become soft.
Once chicken and potatoes are cooked, add palm sugar (you can add less of palm sugar too), peanuts and tamarind paste.
Add the rest of the coconut milk and water , if required. Check the seasoning and add fish sauce or soy sauce if you think it needs more salt. Or else, simply add salt.
Lastly, add basil leaves, give it one boil and turn off the heat.
Serve chicken massaman curry with steamed rice.