2 c. sugar
1/3 c. flour
3 tbsp. cornstarch
6 c. rhubarb, cut up
1 1/2 tbsp. butter

Heat oven to 425 degrees. Mix sugar and flour and cornstarch. Mix lightly into rhubarb. Pour into pastry lined 9 inch pie pan. Dot with butter. Cover with top crust. Cut slits in it. Beat 1 egg yolk with fork. Brush on top crust. Bake 40 to 50 minutes or until crust is browned and juice begins to bubble through slits.