Preheat oven to 375 degrees. Line a 9 inch pie plate with one crust. Mix together sugar, flour, rhubarb, and strawberries. Place filling mixture in pie crust. Dot the filling with butter. Cover with top crust; seal and flute. Brush crust lightly with cream; make several slits in crust with sharp knife. Sprinkle with coarse sugar.
Cover edge with 2- to 3- inch strip of aluminum foil to prevent excessive browning. Bake until juice begins to bubble through slits in crust, approximately 45-55 minutes.