Add the cooked spleen and all other ingredients into the inner pot. Close lid, VENT know to SEAL, set mode to STEAM and KPT 5 minutes. Press START.
After 5 minutes is up, slowly release the pressure manually. Once pressure has been released, carefully open the lid.
Set mode to BAKE Chicken or Saute. Simmer for about 10 minutes, stir occasionally. One sauce thickened, STOP the pressure cooker. The rendang is ready to be served.