Should be made only with fresh rhubarb, in season.
Stew the rhubarb with ¾ cup sugar, in water just to cover, until soft. Cool. Add the milk and the yolks of the eggs beaten with ¼ cup sugar, flour and salt.
Add the lemon juice. Pour into the unbaked pie shell.
Flute a rim to stand up above the pie plate. Bake in a 450 degrees F oven for 10 minutes, then in a 325 degrees F oven for 25 minutes.
Beat the egg whites until stiff, adding the remaining ¼ cup sugar gradually. Beat until glossy. Spread the meringue on the pie and return to a 300 degrees F oven for 10 minutes or until the meringue is slightly browned.