Red Raspberry Streusel Pie

1 (8-ounce) carton sour cream
1 large egg
1 teaspoon vanilla extract
3/4 cup granulated sugar
2 tablespoons flour
1/4 teaspoon salt
1 1/2 cups fresh or frozen raspberries or 2 cups red raspberry pie filling
1 unbaked pie shell

Topping
3 tablespoons chopped pecans
3 tablespoons sugar
4 tablespoons flour
4 tablespoons margarine

Combine the first six ingredients and beat for 5 minutes or until smooth. Spread 1/2 to 3/4 of mixture in bottom of unbaked pie shell. Dot raspberry filling over this and swirl with a fork or knife. Pour in remaining sour cream mixture and bake at 375 degrees F for 30 minutes or until done.

Meanwhile, make the Topping. Combine flour and sugar; cut in margarine until mixture is like coarse meal. Stir in pecans. Sprinkle over pie and bake another 10 minutes or until topping is lightly brown.