Combine the topping ingredients: flour, melted butter, and chopped nuts. Set aside for later.
For the Blueberry Pie
Combine the first 6 filling ingredients(sour cream, flour, sugar, vanilla, salt, and beaten egg). Mix on low speed for 5 minutes with an electric mixer.
Fold in the blueberries.
Pour the filling into the unbaked pie shell. Bake at 400℉ for 25 minutes. Next, sprinkle with the topping. Bake for ten minutes more. Chill before serving.
Keyword blueberry pie, easy blueberry pie, fresh blueberry pie