Preheat oven to 450 degrees (F).
Roll out pastry pie dough rounds to fit a 9” pie plate. Glass or ceramic dishes bake better than metal, but use what you already have.
Combine sugar, flour and salt. Whisk together until flour is incorporated into sugar then mix in the rhubarb, fresh or frozen.
6 cups rhubarb, 2 cups sugar, 1/2 cup flour, 1/2 teaspoon salt, 1-1/2 tablespoons butter. Bake at 450 degrees for 15 minutes, decrease temperature to 350 degrees and bake an additional 50 – 60 minutes or until filling is bubbling.