In a bowl, soak black nuts in hot boiling water, for 5-10 minutes, then rub between fingers, mixing the nuts into dark liquid.

Into a pot, add lemongrass, kafir line leaves, beef cubes and enough water to cover it. Bring to boil, scoop out scums.

Meanwhile, make paste out of onion, candlenuts, garlic, and water. Dump mixture onto a pan, saute in olive oil, along with turmeric powder and ground coriander, until fragrant.

Once beef boiling and scums scooped out, stir in sauted turmeric mixture, stir to combine. Pour in black nut water, stir to combine.

Season with beef cubes and chicken bouillon powder. Cook until beef tender.

Serve soup with rice, accompanied with boiled less, fried onion, bean sprouts, and hot sauce if you like.