Combine rhubarb and egg yolks. Add 1 cup sugar and flour and mix well.
Stir in butter and spoon into pie shell. Bake at 350°F for 30 minutes or until set. Beat egg whites until soft peakes. Continue to beat and slowly add 1/3 cup sugar until thick and glossy. Heap lightly over pie and spread to edges of the crust. Turn over to 400°F and bake pie for about 10 minutes until golden brown.
Notes
This recipe comes from a fantastic cookbook prepared by the Friends of the Grist Mill in 2003 based on some of the most popular recipes in the Tea Room.