Sour Cream Apple Pie

This recipe compliments of Miss Annie who writes, "I found this recipe in my files. I don't remember where I got it, but it's good. I love the simplicity of the recipe."
Recipe makes 1 9-inch pie
Whatcha Need for the Filling:
1 cup sour cream
1 egg
3/4 cups sugar
2 tablespoons flour
1/4 teaspoon salt
1 teaspoon vanilla
2 1/2 cups diced apples, peeled
1 unbaked 9-inch pie crust
Whatcha Need for the Topping:
1/2 cup brown sugar
1/4 cup butter
1/3 cup flour
1 teaspoons cinnamon
Whatcha Do:
- Beat sour cream and egg together.
- Add flour, sugar, salt and vanilla.
- Mix until smooth.
- Stir in apples.
- Bake at 400 degrees for 25 minutes.
- Mix the crumb topping ingredients until crumbly.
- Remove pie from oven and spread with crumb topping.
- Bake 20 more minutes.