I haven't found THE pie recipe yet; however, here's one to keep you busy:

Sour Cream Coffee Cake

½ cup butter
1 cup sugar
2 eggs
2 cups all-purpose flour
1 tsp. baking soda
1 tsp. baking powder
1 tsp. vanilla
1 cup sour cream
Filling: Mix together ½ cup tightly packed light brown sugar, 1 tablespoon flour, 1 teaspoon cinnamon, ½ teaspoon nutmeg, and ½ cup chopped walnuts.

Grease and flour a bundt pan. Preheat oven to 350 degrees Fahrenheit. Cream together butter and sugar until the mixture is light and fluffy. Add eggs and beat well.

In a large bowl, sift together flour, baking soda, and baking powder. In another bowl, add to sour cream.

Add one-half of the dry ingredients to the creamed mixture, then add one-half of the sour cream mixture. Continue in this fashion, ending with a final addition of dry ingredients.

Place half the batter in the prepared pan. Put in half of the filling; repeat. Top with the remaining filling. Bake for 50 minutes.