To begin, crack open the soaked keluak nuts. Scoop out the flesh and mash it into a smooth paste. Set aside for blending into the spice mix. Move on to blending the bumbu.
Blend shallots, garlic, chillies, candlenuts, turmeric, galangal, coriander, and white pepper along with the keluak paste into a thick, smooth bumbu. Add a small splash of water if needed to ease blending. Continue to sauté the mixture.
Heat oil in a large pot over medium heat. Sauté the bumbu until fragrant and the oil begins to separate, about 5–7 minutes. Stir continuously to prevent burning. Prepare to add aromatics.
Add kaffir lime leaves, bay leaves, and bruised lemongrass to the pot. Stir for a further 2 minutes to release their essential oils. Proceed to incorporate the beef.
Add the beef chunks and stir to coat well with the spice mixture. Sear until lightly browned on all sides to lock in flavour. Get ready to add water for simmering.
Pour in the water and bring to a boil. Reduce heat to low and simmer uncovered for 1.5 to 2 hours until the beef is tender and the broth has deepened in colour. Skim off any scum as it forms. Prepare garnishes while soup simmers.
Once the meat is tender, season the broth with salt to taste. Taste and adjust the seasoning if needed. Allow to simmer for another 5 minutes. Transition to plating.
Blanch bean sprouts briefly in boiling water. Peel the hard-boiled eggs and slice in half. Warm the rice and sambal. Gather fried shallots and lime wedges for garnishing. Move on to serving.
Ladle the rawon into bowls with generous beef chunks and dark broth. Serve alongside steamed rice, bean sprouts, egg halves, and sambal. Top with fried shallots and a squeeze of lime. Presentation tip: a banana leaf under the rice adds authentic charm.