1 unbaked 9-inch pie crust
3/4 c. sugar
2 tbsp. flour
1/2 tsp. salt
1/2 tsp. vanilla
1 c. sour cream
1 egg, beaten
2 c. peeled, cored, sliced tart apples

TOPPING:

1/3 c. sugar
1 tsp. cinnamon
1/4 c. flour
1/4 c. butter

Heat oven to 450 degrees. Combine sugar, flour, salt, vanilla, sour cream and egg. Beat until smooth. Add apples; toss to mix well. Place in unbaked pie crust. Bake 15 minutes. Reduce heat to 325 degrees and bake an additional 20 minutes. Remove from oven and sprinkle with topping.