Mix to make a stiff paste.  Spread over cut up rhubarb in pie shell - enough to fill up unbaked shell.  Bake at 400° for 15 minutes, then 350° for 30 minutes until set.  Stir in the middle of baking time to keep it from forming a crust.  Make egg white meringue and spread on top, sealing well to edges of pie crust.  Bake in oven again to brown meringue.  Meringue recipes can be found in most cookbooks.