Use a standard piecrust recipe and line a pie tin. Boil the water in a pan. Combine the tapioca, salt and sugar and add to the water. Boil briskly for a few minutes. Remove pan from fire and stir in the dates, butter and lemon
juice. Keep aside until it cools then pour the mixture into the pie shells. Cover with the second piecrust. Dampen the edges and pinch both edges together firmly. Make three or four large diamond-shaped cuts on the top crust
and bake in a hot oven for 10 minutes then reduce heat to moderate and bake for a further half hour. The pastry should be raw before baking. Serve cold.