Rendang is a traditional food originally from west Sumatra, prepared by Minangkabau people. rendang is commonly made with beef (especially tenderloin) but it’s liver and i cooked myself. Well people also can make rendang with chicken.
And it’s need a long time process to cook this main course.
The word rendang originated from the word Merandang or Randang, which means “Slowly” as it takes a long time process to cook it.
I have a friend from minangkabau and they said to me the philosophy of that cooking process. The philosophies are patience, wisdom, and sincerity.
The Proper choice of beef, heat control, and stirring technique give an effect for the taste.
Traditionally, rendang is served for a special occasions and for a special people, like traditional Minang ceremonies, from birth ceremonies to circumcision, marriage, Qur’an recite, and religious holidays such as Eid al-Fitr/idil fitri/idul fitri and Eid al-Adha/aidil adha/idul adha.
This dish is highly recommended to taste when you visit Indonesia. 
how i cooked normally :
~Use only the white portion for the lemongrass. And Bash them.
~cut the galangal and ginger into a small pieces and bash them.
~cut the liver (i’ve boiled it for about 1h) into a medium square
~for less spicy, i removed the white seeds of red chilli
~blend the spices (garlic,onions, red chilli, including ginger and galanggal) i used blender.
~add oil, and saute the spices then add the lemongrass and lemon leaf in a low heat until it’s aromatic
~add the liver and turn in a medium heat
~add the coconut milk and stir
(i used 2 instant pack for 500gram of liver)
~add the water time to time to boil
When it’s boiled, continue to stir it in a low heat and add water again when it’s about to dry. Cook until it’s getting darker. Finish.
Normally rendang is dark, and dry.
I prefer to not too dry it / darker because i like to poking the sauce hehehe…
I’ve done all the process for about 2,5 hours.
