Here is the peanut sauce recipe. you can prepare the sauce a day before.
Massaman Curry paste 50 gram
Salt 1 teaspoon
Palm Sugar 6 tablespoons
Tamarind paste 4 tablespoons
Ground peanut 1 cup
Vegetable oil for frying the paste 3 tablespoons
Coconut milk 3 cups
Add vegetable oil into the pan until warm and add massaman paste and mix together 30 seconds and generally add coconut milk, salt, palm sugar, tamarind paste. Use medium heat all the time and add ground peanut. Taste it and keep stir around 15-20 minutes. Notice the consistency of the sauce. It should get thicken (it will be more thick when it cool down). Adjust the flavor as the way you like.