In food processor, chop fine the nuts, shallots, garlic, salt, pepper, turmeric, and ginger to form a paste. In a saucepan, combine the paste with water, beef, lemongrass and 1 slice lemon. Bring to a boil. In food processor, crush rice to a coarse consistency. Add to beef mixture. Cook, over low heat, covered, for 2 hours. Garnish with egg and lemon slices.