Spread raspberries in unbaked pie shell. Stir sour cream and combined sugar, flour and salt together, mixing well. Spoon over berries, spreading to edge of shell. Sprinkle top with 2 teaspoons of sugar. Bake at 450~ for 10 minutes. Reduce heat to 350~; bake 30 minutes more or until topping is lightly browned. Cool at room temperature; serve fresh.