1. In small mixing bowl, mix ingredients for crumb topping, adding oats last, and adding just enough oats to make the mixture crumbly. Set bowl in refrigerator to chill. (Mixture will be clumpy until well-chilled.)

2. In large mixing bowl, combine 3/4 cup sugar, 3 Tablespoons flour, the egg, sour cream, vanilla, and nutmeg. Stir until well-mixed. Add apples and toss to coat.

3. Pour filling into unbaked pie shell. Bake at 400 degrees for 30-40 minutes, until apples are somewhat softened.

4. Remove crumb topping mixture from refrigerator, and crumble with fork. Sprinkle over pie and return pie to oven for an additional 10 minutes or until apples test to doneness desired.

5. Chill pie before serving.