Cut the beef tenderloin into small pieces and pound it to make it soft.
Fry the pounded beef in hot oil until crispy. Set aside.
In a pot, combine coconut milk with salt and seasoning. Add the pounding ingredients (galangal, garlic, coriander seeds, pandan leaves) and let it simmer for 15-20 minutes until the meat is tender.
Chop 4 large red onions, 7-8 bird's eye chili peppers, and 3 dried large red chilies into a coarse paste using a blender or food processor.
Fry the chopped onion mixture in a pan until crispy. Add tamarind juice, salt, and seasoning to taste. Let it simmer for a few minutes.
Add the tender beef to the sambal belado (chili paste) and mix well until the meat is fully coated with the sauce.
Serve hot with steamed white rice.