Mom's Sour Cream Apple Pie

My mother has been making this pie my entire life for every special occasion and by request. It is my yummy favorite. It is simple and delightfully delicious.

Mom's Sour Cream Apple Pie

2 tablespoons flour
3/4 cup sugar
1 egg, beaten well
1 cup sour cream
1/2 teaspoon vanilla
2 cups peeled, grated Granny Smith apples
pinch of salt

Preheat oven to 400 degrees.

Mix all ingredients together except apples. Mix well, then add the apples. Put into an unbaked pie shell and bake for 15 minutes at 400 degrees.  Mix a crumb topping  made of  4 Tablespoons flour, 4 Tablespoons sugar and 2 Tablespoon butter. Remove pie from oven after the 15 minutes and sprinkle the topping on top of the pie and bake for another 25 minutes at 350 degrees. Let cool completely before serving.