Preheat oven to 400F.
Beat the eggs in a large mixing bowl.
Whisk in sour cream and vanilla.
Add flour and sugar and whisk just to combine.
Carefully fold in berries.
Pour mixture into pie shell. Bake for 30-35 minutes, or until the centre is almost set.
For the crumble, mix brown sugar, flour, and nuts together. Cut in butter.
Sprinkle crumble over the pie, and bake under 10-15 minutes, until golden.