Bring the milk to a boil over high heat in a 5 to 6 quart (5-6 L) saucepan, stirring constantly to prevent a skin from forming on top. Reduce the heat to moderate and continue to boil for 30 minutes, stirring occasionally. Add the rice and cook an additional 30 minutes, stirring frequently, until the rice has almost disintegrated. Add the sugar and finely chopped almonds and stir for 15 minutes over low heat until the pudding is thick enough to coat the back of a spoon heavily. Remove from the heat, add the cardamom and optional rose water, and pour into a 7 by 12 inch (20x30 cm) baking dish, spreading it with a spatula so the top is smooth. Sprinkle with the toasted almonds and refrigerate for at least four hours, until it is thoroughly chilled and somewhat firm to the touch.