Peel, de-seed and finely chop the marrow. Put in a pan with 1-2 tablespoons of water. Simmer until all liquid is absorbed and the marrow soft. Add the khoa, sugar and butter and cook till the mixture comes away from the sides of the pan. Add the almonds and raisins. Put in a dish, sprinkle with nutmeg and serve cold.
Note: Preparation time 10 minutes, Cooking time 14 hours, To serve 4