Boil in a double boiler milk, rice and sugar. It will take from fifty to sixty minutes for the rice to be thoroughly cooked, and the mixture to thicken. Remove from the fire and when a little cool, add vanilla and the yolk of egg into which flour has been smoothly stirred. Mix all thoroughly together, then pour, by spoonfuls, on hot buttered griddle. Let the cakes brown on one side, and turn over, and brown on the other.