Rhubarb Pie Preheat oven to 425 Cut 1.5 pounds Rhubarb in 2 cm lengths Measure 4-5 cups and combine with 1 cup sugar, 1/4 cup corn starch and 1/4 t salt. Let stand 15 minutes stirring occasionally. Pour in buttom crust and dot with 2 T butter. Cover with top crust and bake 30 minutes Reduce temperature to 350 and bake another 25 to 35 minutes.