Blueberry Custard Pie

1 cup sour cream
3/4 cup sugar
1 egg
2 tbsp. flour
2 tsp vanilla
1/4 tsp salt
2 1/2 cup fresh blueberries
9 inch unbaked pie crust

Streusel topping
1/2 cup brown sugar
1/3 cup flour
1/4 cup butter, softened
1/2 cup pecans, chopped

Preheat oven to 400 degrees.  Combine first 6 ingredients, mix until smooth.  Gently fold in blueberries.  Spoon filling into pie crust.  Bake 25 minutes.  While filling is baking, prepare topping.  In medium bowl, combine brown sugar and flour.  Mix butter in until mixture resembles course sand.  Fold in pecans.  After filling has baked 25 minutes, sprinkle with streusel topping.  Bake an additional 15-20 minutes or until filling is set and topping is brown.  Use a crust shield or loose foil tent toward end of baking so crust doesn't burn.  Let set 15-20 minutes before serving.  May be served warm or cold.